You sound a lovely mum OP!
I’m pregnant with my second and I’m already like ‘omg this is the last time I’ll ever have a newborn!’ And baby isn’t even here yet! So I get it.
One thing I will say is that have you thought about the fact you presumably must have had your first as a teen? You’ve never been an adult without dependants and options. This can be daunting and I think you can have ‘tunnel vision’ that having kids and being a mum is ‘what you do’. If that makes sense?
My lovely mum had her first dc at 19 and then had a baby every 5-7 years, so whenever the youngest started school basically. She’s now 56 and only just stopped doing the school run as my youngest brother goes to college!
She did work alongside raising us and had her own house and everything. But she never had a ‘career’ to climb as needed flexibility for childcare and never had many friends outside of kids as limited childcare.
The past few years she’s gone through a serious depression. Her ‘identity’ has gone and she has nothing to focus on so is finding herself in her fifties. She isn’t ‘picking back up’ where she left off with anything as she’s never been a childfree adult. She doesn’t really know herself outside of being a mother and says everything seems ‘pointless’ as raising her kids was her life motivator.
I think if she’d started her family older, even by a few years it would be different. Or if she’d even stopped at 2 kids. I think it’s easier to ‘find yourself’ go to university, start a hobby, forge friendships in your mid-twenties with your whole life ahead of you outside being a mum, than it is in your fifties when your nearing retirement.
I actually think her having kids was a subconscious avoidance tactic to not have to face life in a way. By staying in the great but albeit restrictive ‘mum of small kids’ world. The perfect excuse/reason to not go for promotion, or have time to make new friends outside of kids, or find a path.
I think it is worth considering this OP because the ‘mum of smalls’ will have to stop somewhere and you’ll have to go through it. It may be easier to do in your twenties than later on.
best of luck whichever you decide!