@fuyu1993,
Uh, I don't think I'd refer to that general area as the "back hip." Looks to be more in the upper butt region, which might make it rather awkward to show off your tattoo to your mom. And you don't want to get the same tattoo as someone else. Instead of a blue star, I recommend a green clover or a yellow moon -- in fact, anything from the "Lucky Charms Selection" would be a good choice.
That being said, it should be remembered that tattoos, especially those that you get when you're underaged, are god's way of reminding you as you mature into your later years that you were once young and extremely foolish. I say "go for it!"