Keep in mind that the cup sizes will make a difference, too. Try a 32C, maybe? The cup will be bigger than a 32A or 32B, so maybe it won't feel so snug
Also, I am 5'5'' and about 130lbs, give or take when I weight, so very similar to you. Our breasts look similar, as well
From calculators I've found, it says that if your number is odd, you add 5 inches and that's your band, even add 4. My ribcage measures 30", so I wear a 34 band, and it seems to work. Also, as far as cup size, don't get TOO into measuring...online calculators try to tell me I'm a 36A or even 36AA, which is NOT right. Go by what feels good. Right now I'm a 34C, but don't own any bras so I smoosh my boobies into my old bras. I wanna save my money to buy 34ds! Oh, and as far as the being super skinny thing/32 band size. Again, go with what feels right...but I know that I could NEVER fit a 32 on, they are WAY too tight. Again, if the cup is bigger, it's OK...it's that whole sister bra size thing...34b=32c, for example...but really, 34 is just so much more comfortable to me. And depending on how your body is proportioned, it wouldn't be completely odd to wear a 32. Just go with what feels right.
GOOD LUCK NOOGLING!!