I could've written this exact post 8 months ago.
Had my daughter 2 weeks ago, aged 38, with a very high bmi.
What's done is done, you can't change your weight now and nor should you try.
The aspirin is a good idea, I took a low dose (75mg I think - baby aspirin) daily from start to end. I also was prescribed 5mg folic acid and I took a daily pregnancy vitamin.
Focus now on taking care of yourself. Try to eat as healthily as you can and try to stay as active as you can however DO NOT make any drastic changes.
Trust your body and listen to it.
I'm one for giving good advice but not taking it. I struggled with food aversions throughout so basically ate crap the whole way through, on top of which I have a desk job so was very inactive.
My daughter came at 34 weeks, 2 weeks ago, perfectly healthy. I'm told she came early most likely due to me having an emcs with my first - didn't know this was a thing but i wasn't ever given the impression it was because of my size or being unhealthy.
You will be ok. Take a day at a time and try your best to take care of yourself x