What kind of bikini should I get?

I'm 15, 5'2 and 105 pounds. I'm working out to tone my stomach. I'm not fat, though. My bra size is typically 34a, but I can fit into a 34b, so Idk. What kind of bikini top will make me look bigger up there? I've heard halter tops make your boobs look bigger. Is that true? I don't normally wear bikinis, but I want to start wearing them more. I just don't want those revealing string ones where I have to check every 5 minutes to see if I'm still covered up.