You can't - you will have to wait until you are 18.
"Age is important. You must be 18 or older to be legally liable for signing a contract. "Legally liable" means that legal action can be taken against you if you fail to follow through on your promises.
What about if you are under 18?
Ask your credit union if they will allow you to borrow money with a co-signer.
What's a Co-signer?
A co-signer is someone who is 18 or older, who is qualified to sign the loan agreement.
Whoever co-signs for you agrees to repay the loan if you don't.
Not many financial institutions will allow someone under age 18 to take out a loan. Ask anyway�they may have some other, better ideas to help you get the money you need!"