I understand how you girls feel. It's becoming more and more common for kids to date younger. But just because it's common, does not make it good.
Yes, I bet some of you girls are very mature and responsible at age 12, I mean, I started dating at 14, that's only two years later. But two years can make a HUGE difference. While you may not get into any heavy dating stuff now, starting to date earlier can have a negative effect.
These relationships do not last, which begins to de-sensitize both the guy and the girl. Meaning you get more used to breaking up with someone. This can actually create a change in you mind that tells you it's normal to break up. So once you're older and in a relationship with real potential, you may find yourself breaking up with the person, not because it's going badly, but because your brain tells you it's time, that's how you've always done it.
Dating may seem like a fun thing to do now, but it can be very damaging to you.
I would suggest you just make a lot of guy friends instead. That works on the social skills you will need to have to be a sucessful dater, without causing you any heartbreak or pain.