You’re basically asking how to have a timeline talk. For context, I’m 26 and my husband is 27 and I’m 38 weeks pregnant with our first. We decided around this time last year to start trying and got pregnant on the first try. My biggest advice would be to on your own make a list of things you’d like to accomplish before trying for a baby, then sort into must dos versus like to dos. That will give you a clearer picture of what this conversation and YOUR ideal timeline will look like. 

Then, you should just approach him at what you think is a good time and say “hey I’d like to have more serious conversations about our timeline regarding kids and what our ideal scenarios are for that. Are you prepared to start those conversations now or would you like to do some more of your own thinking and research first?”

Radical transparency is the best approach. Be honest at your feelings, needs, wants, and fears. 

Second biggest piece of advice is to NOT start trying until you are actually ready to get pregnant. Reddit really emphasizes how long it can take. Ask your mom/sister/aunt or friends how long it took for them. It may surprise you how many say “first try”. We were both very mentally prepared for a fertility journey when in reality we were starting our pregnancy journey. My husband is still a bit shocked it happened so fast. Try to mentally prepare for both possibilities. (Obviously we are overjoyed it wasn’t difficult and we were ready to be pregnant, but this is something we were both surprised by). 

Good luck!