Urge to be pregnant...

So I've been sexually active for the past year. I lost my virginity to my current boyfriend. We've been dating for a year and a half and I just have random urges to be pregnant with his child. I know both of us are no where NEAR ready for a kid, financially or otherwise but i feel like I want to have his baby. Both of us have talked about the marriage route/moving in together/etc so I know its serious. Hes said he loves me and treats me very well. Im just worried that I want to have kids right now. Im only 21.

Is this normal?

Is there any way to get rid of this "baby fever"?

Help! Please :)