take this as a BIG warning. stick to using localbitcoins.com to buy bitcoins. then transfer bitcoins to an exchange, do some trading to increase your bitcoin holding, and take bitcoins out to then sell for fiat back at localbitcoins.
i tell you this as a warning. because by using the service underage means they COULD lock your account without any warning and due to the fact that wire transfering to underage users is against their policy, they will not honour a wire transfer if they found out your age.
so DO NOT even risk doing a wire transfer or even getting verified with bitstamp. it is not worth the risk/cance of getting your account locked. so stick with only moving bitcoins in and out, thus avoiding the whole verification process of fiat transfer.
again DO NOT RISK IT moving fiat into or out of bitstamp. if you do then you have only yourself to blame.
localbitcoins is the less riskier option