I was 25 & 27 when my kids were born. I always thought it was plenty old enough, though my daughter is 24 now and I see it a bit differently now. Most of their friends' parents have always been considerably older, which made us the cool parents most of the time.
Waiting until you are older has some benefits, but think about the other end, too. I'm 49 and both kids have been on their own for a couple of years. Having an empty house and more freedom from the responsibility of being a parent at a relatively young age also has a lot of benefits. Life is good. I cringe when I see parents our age and older with teenagers at home. Ain't nobody got time for dat.