Should I get braces if I don't need them?

I surprisingly have the choice, I don't NEED to get them, I can get them for cosmetic reasons to make my bottom teeth look good. My dentist said all my other ones were perfect, but the bottom row wasn't. They're a little crooked and misshaped, but when I smile you don't see my bottom teeth. Also, could you give me a price range? I haven't gone for a consultation yet, but I'd just like to get an idea. By the way I'm 13.