Baby fever!

Is it just me or!?!? I'm 17, turning 18 in a few months and everytime I see a baby my heart just melts! My boyfriend and I have been together for about 3 years.. He's 19. His mom had a baby that just turned 6months old yesterday. I live with him also. I know I'm young but I just want a baby already!! Watching him with his little brother literally just makes me want it even more. We both agree we are too young so we are careful, what do y'all do to help this??!