Most Helpful Guy
As others have pointed out, it might be illegal where you live, depending on what you do together. Check the law.
My personal opinion is that private relationships are an individual decision and the state has no business poking its nose into your romantic life.
I also think that if you make decisions you should accept responsibility for the consequences. If you think you're mature enough for all the good fun and easy bits of a relationship with this guy, please also spend some time considering the difficulties, what can go wrong, health and legal risks (if any).
Most Helpful Girl
Slightly strange. You two live in different worlds. He is able to go to bars and casinos. He is able to vote and apply for credit cards.
You are in high school and can't legally do any of the things above.
If it works for the two of you, great. Hopefully you live in an area where that is the legal age for consent.