Future MD, come now... I majored in psych too, let's not get overly defensive... after all, the only stupid question is the one that goes un-asked, right?
Anyway, as for your question, it is really a two-parter:
1) Can they find out?
2) Will they try and find out / Can it hurt me?
As for #1, I can give you the information that I know. As long as you see a psychologst or psychiatrist in private practice there is no way for anyone to find out from your therapist because they are bound to confidentiality as per the rule of the doctor-patient relationship. There are two caveats to this, namely if you check into a hospital with a psychiatric emergency or if you have insurance pay for it. In either case, there will be records showing your medical need for counseling that are outside of the control of your physician (be it either the hospital or the insurance company), and they may give it out to others (such as your Med school) without your expressed consent and without violating any laws.
As for #2, I don't honestly know. I sincerely doubt they do, because I know a handful of people who are currently attending or who have attended top medical schools who were seeing therapists throughout most of their college and graduate careers.
My advice to you, take it or leave it, is that if you can afford it, get the counseling. But don't try and use your insurance to cover it if at all possible. Your mental health is more important than anything else. Sometimes we forget that in the rush to be successful students, physicians and people in general. Your obviously in touch enough with your emotional needs to realize you need to sort some things out. Take advantage of that now. Otherwise, you'll find your functionality, your ability to handle the ups and downs of daily life, will start to be impaired. And that's not something a med stundent can really afford to have.
Good luck