im no expert on art but if you truly enjoy it go ahead.
but be advised that art is a very coursework heavy subject (basically all of my friends doing art complain about it in school) and you should read the specification from the exam board to make sure it's something that you'll enjoy.
if you cant handle all the coursework then maybe its best to choose another subject but if you think you can balance the coursework along with regular revision for other core subjects and if you enjoy art then go ahead :3