I don't think you should. I find it unnecessary being that you have a pretty nice looking belly button. I've noticed that women who get belly button piercings usually get it because they're trying to balance the appearance of their belly button hole because the hole is larger than normal, but your hole is a nice perfect size. Plus you might not want the piercing when you get older and even if you take it out, that hole will always be there, and the piercing hole is going to get stretched out the longer you have a piercing in there, so it will look weird when/if you eventually take it out
