Need advice!

So me and my boyfriend will be together for 4 years in August. I always tell him I want him to purpose to me soon. We talk about having a family and getting our own apartment together and moving to Florida once I'm done with college in 2 years. Well the other day he said to me "I wanna have a kid". I really want to have a baby with him as well but I really want to be engaged first. I don't think he has any intentions on purposing to me before he tries to get me pregnant. But the thing is though if I tell him I want to be engaged first I'm afraid we'll never have kids because he's not gonna marry me until we're like 40! If he would purpose to me right now I'd say yes and start trying to have babies tomorrow! My thing is I just really want that commitment before we bring life into this would. What should I do?