My late DH was the same way. He was never ready for children, and I was ready at a young age. We didn't start trying until I was 27, and we got pregnant pretty quick (ended in a m/c) and he passed away before I could try again. Luckily my OH now is fully in support of children.
I guess where I am getting at is, 1) talk with him more and find out what he wants to accomplish before trying (buying a house, more traveling, skydiving..whatever it may be). His mind might change when he gets older. But ultimately, if you are both not on the same wavelength about children (in that he doesn't want them), you should really think hard if you are willing to sacrifice not having kids for him, or if he is willing to give in and set a date for trying.
When I started dating again, it was one of my requirements (because I am nearly 30) to make sure that the person I started dating seriously did want to have kids, and didn't want to wait 5-10 years (because I am nearly 30). I just don't want to see you resenting him because you don't get what you desire out of a relationship, or him resenting you because you pressure him into something he does not want.
It's a tough situation to be in, I have been there.