I don't think that I am really in a position to say one way or another what "exactly" adcoms will think about each and every applicant - but I'm guessing that most are really conservative - and if nothing else, consider that this is a professional health care interview that you are going to. For my interviews I've gotta take out my earings (I'm a guy by the way) and shave with a razor - i can't stand not having a scruffy, 5o'clock shadowish face. so I suppose if you are in doubt - chop it.
I mean, if you knew ahead of time that (hypothetically) shorter hair would be equal to a 15% better chance of getting accepted - would you cut it?
yo - stop messin' around and just get a sweet wig.