I'm only 17 years old but I've been feeling maternal hormones lately. Every now and then, when I see a guy that I like, I'd mentally make babies with that guy. Now what this means is that I'll ponder over the boy's looks and then try to mix them with mine to see if I can mentally imagine our kids. Then I'd proceed to think, "We'd make cute children" or whatever. I thought it was just a harmless game to play with the people I have crushes on, but some of my friends think that it's weird. My question is do YOU think it's normal?

You're too young for kids. I'm 20 and proud that my husband and I have managed to keep from getting me pregnant, lol. My advice to you, don't be afraid to talk to your parents about birth control. They'll understand you, and they'll probably greatly appreciate the fact that you asked about it BEFORE you go steady with anyone. Make sure the guy is there for YOU and not for your goodies, too.
I'm sure you already know all this though. Stay safe. :3