We knew each other about two years before we moved into together, married about 6 months after that, and I had a positive pregnancy test about a month and a half after that.
I don't think it's pressurising to have an in-depth discussion and ideal timelines for the future, working through your thoughts on the risks, responsibilities, and benefits on thinking with the understanding that some of the details may change. He may know your feelings that you want to have kids or other life choices, but there is a lot to consider. If he doesn't want to talk about it, that would put me off.
While I think it's very important to discuss and layout the ideas around kids before marriage, I'm on the side that that should be considered first. It isn't an assumption, legally and statistically having children before marriage is riskier in several ways. For some that risk is worth it, but I don't think it can be overstated in a 'it's just a piece of paper, it's all about the love' culture that there is more than that.
Divorce rates are on a pretty steady decline - this year may throw things off, but in recent years we're at the lowest point since the early '70s, and for a first marriage in the mid to late twenties, without a child already involved, death is the most likely cause of the marriage ending. Waiting later (I think the rates start rising after 32 or so, but that may be because there are more second+ marriages going on) and after kids only raises the likelihood of divorce.
I think people can mostly take the risks and responsibilities they want for the benefits they seek, but looking at divorce statistics really shouldn't put most people off marriage before kids.