What size contacts are usually common for a teenagers eyes?

I am getting non prescriptive colored contacts and i need to know what size to get!What size contacts are usually common for a teenagers eyes?
well depends!!! cuse im 14 and my eyes are horrible, my lens strengh is -7.5!!!! so it all depends!!!What size contacts are usually common for a teenagers eyes?
Depends. All teenager varies. Try asking your doctor for help.