Is this bad?

I'm 21 years and and my boyfriend is 22, we just bought a house and we've been together for 3 years and best friends for 5 years before that. We're very happy together and I hate to say this but i really want to start a family. I would prefer to be married first or at least engaged and we're both on the Same page with that. But I have CRAZY baby fever for some reason and every time I get my period I get kind of sad. I still take my birth control every day and we use condoms because a baby isn't in the plan for now. But I really want to be a mom. Is this bad? Am I too young to have this "baby fever"