At times I get serious baby fever...

Alex • 23 | soon to be abdominal & OB/GYN Diagnostic Medical Sonographer May 2020 | taken and not TTC
I'm 19. I have a bf of 3 years and he also has said a few times that he wants kids now and can't wait till we can. We both know not to right now cause we wanna make sure we are married if we have kids and have careers set up. But sometimes I seriously just want all of that now but also am kinda apprehensive because I always hear how hard marriage can be and bringing a kid into it would be tough.... 
I'm a very stern person and prolly critical too. So if I get married and my husband does something very wrong or something I've made clear that I don't like, I don't think I'd be strong enough to work things out and stay together. Is it just me?