DON'T sign any papers until you have taken them home and read them over carefully. If you ask for a copy of the enlistment agreement, they must give it to you. If they refuse, don't sign the agreement. Talk the enlistment agreement over with your parents and friends, and with a trained civilian counselor. Ask about the parts of the agreement that you don't understand.
Spoken promises are worthless.
Get copies of everything you sign. Keep the copies in a safe place. Early discharges that don't also punish you can be hard to get. Think about all of the job experience you have. Don't forget to include volunteer work, baby-sitting, home carpentry, or painting.