I'll be 38 when my baby boy is born, so no :) you haven't waited too long! You will have two families, so to speak, with your kids being so far apart in age, the baby won't be close to his/her siblings.. but if you're OK with that then there is no reason for you not to have another one. You might find that you need some help though, I had to go on clomid to conceive my son. If you try for a year and nothing happens, you should talk to your doc about it.
Personally, I am ready now to be a mom, my husband and I are financially stable and both at a place in our lives where we can "smell the roses". I wasn't ready in my 20's .. I always found a reason to wait.. next thing I know my daugther will be 17 when my son is born!