Lots of different information and opinions so sorry but here's another.
I lost 3 before having dd...at 28. But I fell pregnant very easily. First time on the pill', taking properly no antibiotics or anything.
Within my circle of friends I have extremes from one who fell while a teen completely unplanned through to 3 who 2 have had their first babies in last couple years one is pregnant (we're mid 40's). 2 of those had major fertility issues the 3rd has a chronic health condition which on the surface is unrelated but had a knock on effect. 3 have had stillbirths (though one was because of a drunk driver), 7 of us have had mc and of those 5 multiple mc. It's not just about conception. If someone goes through a mc, stillbirth, difficult birth for some reason they need time to recover.
I also agree about it being knackering.
BUT I'm concerned about you being pressured, if your dp has any real life experience of young babies, understands the financial, practical and emotional stress a baby brings.
I love my dd to pieces and would never be without her but...
Ex was an immature arse who did bugger all father wise. He expected me to have 6-week check and then 'the baby would fit round our life' and yes I was an idiot having a child with him.
Meanwhile several things might get across the seriousness of this to him
Letting him know as far as you're concerned you want the financial and legal protection of marriage first.
Get both your fertility checked and general health that may affect things.
'Borrow' a baby (or 3
) for as long a period as possible so he can experience the practical realities - and don't you do all the childcare.
Work out what your budget would be while you were on may leave or if you left work, and live on it for a month? Good way to save for Christmas!
Review your contraception and protect yourself before the decision is out of your control.