My boy friend got a passion charge while he was 17 but didn't go to court until he was 18 and now is going to be 21(in march) and wants to become a marine and I was wondering if that would make him ineligible to become a marine?

I'm not sure what a "passion charge" is. Any kind of felony is frowned upon in the Marine Corps. They like the records to be clean.
The USMC can give your boyfriend a felony waiver, but I wouldn't count on it. Why doesn't he sit down with a recruiter and work something out?

First the age he went to court has nothing at all to do with it, the age he committed the crime does.

At 17 in many changes they are still charged as a adult.

Next, having passion is not against the law, having sex with underage child is, public indecency is, hiring a hooker is.

So tell us the change for more info

My fiance' just joined the marines && is currently in basic training. I know they searched his record && looked at everything even as small as a parking ticket. As Jaime90 said, they want their Marines to have completely clean records.