Was that statutory rape?

Yes, it was something illegal according to the law, you should check the laws in your state to verify whether it was specifically statutory rape or child abuse. All of this is based on the law, and how you felt about it doesn't matter for the law. If he did what he did against your expressed consent, it was also rape in the general sense, but few people believe it's a consent you can express at that age.

Possibly? its hard to be sure. I dont think changing your mind after the fact makes it rape technically, at the very least its unfortunate. Im not sure, but I feel like I was fully reasonable and conscientious at 12, even if i was immature. So I think its more important to figure out if you are ok with it now.

Technically, yes, because you were underage and he wasn't. But it all depends on the relationship. Do you feel he coerced you into it? Did you give any signals that you didn't want to engage in sexual activity? Did he ignore these signals? It all depends how you feel about it. Some would argue that a 12 year old wouldn't really understand that they could object etc. Depends on you personally.

Nah, you're alright.

Technically and legally that is rape, yes. I think especially if you're thinking it was too early and you weren't really consenting (which, again, you legally couldn't anyway). Unless you plan on reporting him or anything you might want to try to focus on how you are dealing with the situation. Like, if there's anyone you can talk to and tell what happened, I think that might be a good way to get some closure and to heal from the experience.