Can i join the marine corps at 17?

if they are together or share custody then yes you will need both parents to sign off on it.

just tell her calmly she can either sign , or you will be enlisting anyway at 18 and will resent her for making you wait.

you can only leave early if you've graduated high school already. if you're not going to graduate until you're around 18, just wait and enlist then. then, you don't need anyone's permission accept your self, and the recruiter to make sure you're qualified.

you can see if your high school offers the ASVAB to students interested in the military. see if you can take that early to get a head start. i believe the scores last up to a year, but I'm not sure. talk with a counselor at school.

With both parents and a HS diploma.

Only if you sit on a balloon in booty shorts.