I fell pregnant with Riley at 38 and had no trouble, I had a miscarriage the previous year and had stopped trying so decided to try again and fell very quickly but everyone is different. I found I was more achy this time but whether from age or the fact I already had 2 children its hard to know lol. I had far worse braxton hicks at the end too but again this could be 3rd child thing not age. All in all the pregnancy wasn't a lot different although I don't think my body had bounced back as well afterwards!!!!
I am enjoying this baby much more and am more relaxed and happy in myself than I was when I was younger. I enjoyed being pregnant more because I didn't have the body image issues I had in my 20s.
Good luck, there are plenty of women out there having babies in their late 30s and early 40s so you won't be alone.