hi

first of all congratz on your winnings ..
I want to suggest you don't withdraw to coinbase account beacause i heard some peoples account frozen because there btc coming from gambling sites..and when you want to use exchange site before using it try to know is that site ligal or not. There are so many exchanger ran away with peoples money.you can ask here legit exchange site name.we can let you know but before it where are you from? Its important.

Good luck