For someone who had been working in the Assembly for Sinn Fein since 1998 - she was just 21 - as a political advisor to the Mid-Ulster MLA Francie Molloy, who was elected in her own right in 2007 and who served as a minister in both the Department of Health and Department of Agriculture and Rural Development, there was still quite a lot of surprise when Michelle O'Neill was chosen to replace Martin McGuinness in January 2017.
Outside the very small circle which controls Sinn Fein, the smart money was on either Conor Murphy or John O'Dowd to succeed McGuinness. Only Gerry Adams, McGuinness and one or two others - including Mary Lou McDonald - will have known the specific calculation behind O'Neill's elevation and it's unlikely that information will enter the public domain.
At the time, a Dublin-based TD noted: "The decision was made by two or three people. The ard chomhairle was consulted after the fact." When I asked a Sinn Fein MLA (who I think was in the Murphy camp) why O'Neill, he replied: "It is what it is, Alex."
But it's hard not to conclude that Arlene Foster was key to the decision, particularly since Sinn Fein was keen to push for an early Assembly election and probably thought their chances might be better if Foster faced another female, rather than someone like Murphy.
If so, it was a decision that paid off, because, in March, the party was 1,200 votes and one seat behind replacing the DUP as the largest party. As it was, the election resulted in unionism losing its overall majority. It was a spectacular result for someone just a few weeks in the top role.
Another factor which favoured her was that, like McDonald, her personal past was a clean one. But being Northern Ireland, the past of members of your family can be just as important as your own. Her father, Brendan Doris, had been a Provisional IRA prisoner and Sinn Fein councillor and two of her cousins were also IRA members.
When her father died in 2006, Martin McGuinness described the family as "a well-known and respected republican family, who have played a significant role in the republican struggle for many years".
She ticked two important boxes for Sinn Fein: unionists wouldn't be able to attack any personal activist/terrorist roots and nor could anyone in the republican family claim she didn't have the necessary family connections to be the leader of a party that still venerated the "heroes" of the "armed struggle".
As Francie Molloy (maybe the closest she has to a mentor) told me: "She hit the ground running when she started to work with me... and has moved through the political process, having worked at grassroots level to become DFM (Deputy First Minister)." That support, of course, is vital to her.
But, while she may accept the description of herself as a new generation republican, there is still a sense across unionism that she is not yet "new" enough to distance herself from the IRA's campaign, let alone be seen to be critical of it.
That may explain why she got it so wrong at the time of the Bobby Storey funeral - even though she now seems to acknowledge that mistakes were made.
What was required from her before the funeral was a very clear message that people should stay away on the day. She could - and should - have pointed out the unique circumstances and the health risks involved for hundreds, even thousands, of people, saying that, while Sinn Fein would send a prominent member to represent the party, it wouldn't be her, or any elected representative and finishing with the promise that there would be a properly organised commemoration event at a later date.
She didn't, of course, take that approach. And in not taking it she did considerable damage to the Executive's collective message, as well as to her own reputation as a fairly safe pair of hands.
This week, the Belfast Telegraph published an opinion poll by LucidTalk, which indicated that O'Neill's personal approval ratings were, at 22%, lower than every other party leader. While it's true that the rating probably won't damage Sinn Fein's election chances (the party is actually 1% ahead of the DUP), her standing has been massively damaged within unionism and, crucially, with voters who fall into the Alliance/Green/Others category.
It's those voters which Sinn Fein needs to win over if it is to have any chance of victory in a border poll, or replacing Foster as First Minister.
For all the fact that her handling of the crisis a few weeks ago - when she clearly prioritised Sinn Fein interests over wider community interests - has damaged her in the short term, it's not so clear that its impact will be lasting.
A senior civil servant, who got to know her when she was Minister of Health, told me: "She was warm, affable, open and not afraid to say if she didn't fully understand something. That's actually quite rare for a minister. And she also had a very light, personal touch; that same touch (Martin) McGuinness had, which is maybe why he was so keen for her to take over."
Ulster Unionist councillor Walter Cuddy, who worked with her on the old Dungannon and South Tyrone Borough Council (she won her father's seat) added: "It was obvious from day one that Francie Molloy and Sinn Fein had high hopes for her, because she was fast-tracked to positions of responsibility above other, more established, Sinn Fein councillors. She was approachable and would listen to your point of view and worked well at councillor level."
That said, when she was mayor in 2010, she hosted a ceremony for a former councillor and IRA member, Martin McCaughey, who had been killed in 1990 and unveiled a portrait of him in the mayor's parlour.
A number of unionists I have talked to about her since she succeeded McGuinness three years ago have spoken warmly about her, acknowledging her affability and hoping she might be able to repair some of the damage done after the Assembly collapsed in January 2017.
One made a very interesting observation (just after the election in March 2017): "She doesn't have the personal baggage of Martin McGuinness, yet look how much he was able to do, even with that baggage, in terms of working with (Ian) Paisley and (Peter) Robinson. She has a chance to reach the parts of unionism he couldn't: not to convert them, obviously, but to establish a new way of working together. Let's hope she and Arlene can get the Government up-and-running again soon."
When I spoke to him again at the time of the Storey funeral, his original optimism had diminished: "I worry now that she isn't ever going to be willing to challenge her base in the way that both Trimble and Paisley did - and McGuinness also did. Her response to the funeral was a chance to lay down a marker. She didn't take it."
I wonder if her lack of boldness might have been something to do with John O'Dowd's leadership challenge last year, which he said would provide the opportunity to "debate across the party and island". But the party's ruling ard chomhairle declared there would be no hustings events, curtailing debate and stopping leaks about differences, and was very reluctant to reveal the final vote (she won with 67%).
Still, O'Dowd's 33% indicates there are differences and that support for her isn't overwhelming.
Trying to limit the turnout for Storey's funeral would probably have angered a key demographic within the party and been portrayed as "rolling over" to the DUP.
Sinn Fein will continue to prioritise the unity project above all else and is determined to see rising support in the south matched by rising support (especially from "Others" and anti-Brexit unionists) in the north.
LucidTalk's poll suggests a fall-off in support here. And while it is not catastrophic, it will still worry key strategists and some people who would have preferred that the leadership hadn't been "gifted" to her.
There is no threat to her leadership, but there are people wondering if she is as good at it as McGuinness and Adams would have hoped.
Has she the boldness required to lift those personal ratings?