What tampons do you think I should use?

Hi :) I have decided to use tampons as pads seem to leek and I hate the feeling of blood coming out of me. I am 15 and I don't want to be standing clueless in the female section of some drugstore wondering which ones to buy. I have really heavy periods and I am on birth control for them, my l hole is really small and I am a virgin.. are there any thin ones? thanks (: