I mean, yr size is relevant, since that determines where you can actually shop. In particular, if you are small-band-and-big-bust-ed out of mainstream US brands (which a lot of women actually are, without actually being aware of it), that's when you have to start looking abroad and knowing what's up.
In any case. If you do fall into that category, there are old standby UK brands like Panache and Freya, although those price points are a bit steep for an 18-year-old ($50-80 per piece, but WELL worth it for the fit).
If you are... uh... good at standing up for yourself against usurious extra paypal fees (lol), then there's the Polish brands -- I've been in love with Ewa Michalak and Comexim lately.
But... that's me.
More generally, you should head over to the "a bra that fits" community on reddit (http://www. reddit. com/r/abrathatfits). That's a pretty big community, and it's absolutely *guaranteed* that you'll have at least a few "size twins" over there who can give you some personal recommendations, with regard to fit, price point, comfort, support, style, bla bla bla.