Well, if they're really that small, it'd be the GUY who's working himself up over nothing, right? To quote the great Moe Howard, Ba-ZING! But honestly, there's nothing to worry about.
And even if there were, worrying about it would literally do nothing but make you less dateable and more depressed. It's a vicious cycle that can end only with you foolishly attempting to shout your own breasts into line on a crowded city street and promptly being gunned down by an overzealous rookie cop. If I've seen it once, I've seen in a thousand times (although I've yet to see it once).
Everyone's got weird body stuff. I'm utterly convinced the left side of my face is just the eensiest bit paralyzed, which is why I've overcompensated in my avatar photo. But the big secret is, NO ONE NOTICES BUT YOU.
And by the time you've made a connection with someone deep enough, and spent enough time together to start noticing all the places you voided your body's warranty or it just plain came out of the factory wrong (the factory being a vagina in this case), you'll be well beyond caring about such trivialities.
In fact, the REAL secret is that they become incredibly endearing. I don't care that my wife's boobs aren't exactly the same size, but I LOVE trying to verify it by hand.
You presumably rock, so keep the confidence up, lead with your strengths, and play the shit out of the hand you've been dealt. Everyone has things they're proud of and things they're ashamed of; why let the downers control your brain? Focus on the positive things about yourself and so will they.