How do i get myself to feel more confident in my body?

This summer is supposed to be great because i just graduated 8th grade and i was planning on partying a lot, and hanging out with my friends at the pool and things. But no matter what anyone says i still feel uncomfortable with my small chest. i did buy a push up swimsuit top but it doesnt feel right. i realize that skinny people arent normally the really busty type, and that many girls are the same as me, but just having to think that way doesnt feel right either. Some people say to wait for them to grow, but i dont think they will becuase my family is all kinda flat, like my 22 year old sister who is a 34A. ya i probably sound whiney, maybe im just really overthinking things. any help would be appreciated! thanks :)