Not necessarily.. Completing the ASVAB is part of the enlisting process at your given MEPS
Enlisting.
That's a decision only you can make for yourself. Everyone's nervous about enlisting in the military to some extent, no matter what they tell you.
That depends on your schedule.
No enlisting in the military at 17 does not make emancipated.
No, and you may be prohibited from enlisting after your probation is discharged.
Studying for standardized exam for enlisting
Yes. You only need parental consent if you're enlisting at 17 (which is the minimum age of enlistment).
you may but only noncombat jobs
Yes you are and yes you can.
Some options are promotion, commissioning, or enlisting.
Yes. You can join the US military without being a citizen, so long as you've established permanent residence and have declared an intent to obtain citizenship.