I teach students of 18-21. Sometimes they talk to me of their future aspirations. Anecdotally, based purely on these conversations I'd say the prevailing winds have been blowing in this direction for quite a while. They're not talking about the big career; they're talking about marriage and children.
I'm Gen X. This was a generation of women who valued independence and focused on careers and living for themselves first, rather than prioritizing marriage. It's a generalization, I know, but it was a recognised discourse of the 90s and 00s. I married in 2008 aged 36 and kept my own name, as did the majority of women in my profession. Some had children later. Others opted not to have them at all. Then we were told that was wrong too (aren't women always?), that we were squandering our fertility and 'natural' roles as mothers, and that instead of selling out to the patriarchy, we were selling out as corporate kiss-butts instead. Younger women came along and saw the 'superwoman' phenomenon, where some women in full-time careers ended up with the bulk of the housework and childcare still laid on them and thought - probably quite reasonably - 'fuck that'.
Because, for women, it always seems to have boiled down to a choice between career OR family, and as for the spoiled harpies who wanted to 'have it all' (ie both: a thing men have always taken for granted), well that's (yawn) 'SELFISH!' And we all know that's the worst accuastion that can ever be levelled against a female because how the hell dare we?
Okay, this has turned into something of a rant. Basically it's the sort of generational shift we've seen myriad times before, and there does seem to me to be a trend toward marrying younger (and avoiding managerial responsibility in some professions too). In your shoes ,I'd actually likely feel much the way you do, but what I would do outwardly is be delighted for her and keep my opinion strictly to myself.
The economy is shot to shit and the university system dying a death so who is to say the likes of me were right and this generation wrong? The interesting question is where all this will end up.