Do most schools let you know reasons for rescinding or annulling your application. Do they state the terms and conditions in acceptance letters?
They will not tell you why you were rejected. Most schools will tell you the basis they use for rescinding an offer of acceptance (usually falling grades or disciplinary action) so you should know why you are being rescinded.
Acceptance letters typically have some wording to the effect that the acceptance is contingent on your maintaining the same academic and personal standards. Each college has its own criteria but a general rule often quoted on CC is to avoid D’s, F’s felonies (and more recently offensive internet posts). You also must graduate HS. So I recommend you continue working hard in HS and keep out of trouble.