It'sa important to knbow how the stock is registered (whose name is it in) and where and how it;s being held

If it's only in your name - you can not sell it until you;re 18,

if it's in the name of a custodian for you, have the custodian sell it

If it is being held by a brokerage firm,,in your name. have a custodian give them instructions to sell it

So sell it.

(But realize that any taxes due on any gain MUST be paid by the person who bought the shares for you, since you are not yet 18...when you sell the proceeds will go to whoever's Social Security Number is on the brokerage account, which also will not be you since you are not yet 18...)