J.F.
If you're even considering it, then I would say "Yes - go for it!". Seems to me like everyone I know who is done having kids KNEW they were done without a doubt. We were in a similar situation - I have a 4 year and a 2.5 yar old and am expecting again in 5 months. I will be 37 when the third is born and although there are risks as we age, if you're healthy and have healthy practices while pregnant, the odds of having any problems at 30 years of age shouldn't be an issue. Good luck!