Your chances are 50/50. In the most industrialized nations, especially the US, the birth rate is lower than the death rate, leading to decreasing populations. That's because many people are choosing not to have kids. Some don't want the responsibility. For others its the restraint it imposes on their time. And then again, kids are expensive. The US Dept of Agriculture estimate, for a family with a gross income of under $56,000, it will cost almost $160,000 to raise a child, birth to 18. And that is just the bare bones care, so if you're an extravagant parent, it can climb dramatically. Wow, at least $9,000 a year to raise a kid.
I guess, to get back to your question, it really depends on the feel you get for the guy. Is he really adamant about it or is he more equivocal about it. And 'words' is right, how long would you be willing to wait to find out? If you're looking to start a family young, then waiting may not be possible.
And, from a guys perspective, men are generally less interested in having a family when their young. 30-35 is really when guys start to think along those lines.