Does it matter if I accept the offer from an university later?
How does it affect anything?
Can it affect classes I enroll into?
Did they offer you any kind of scholarship that had a acceptance date. Typically when your offered admissions to a school your next step is send a deposit for your housing and sign any paperwork required for finanical aid. You are typically not required to accept admissions immediately when informed of the decision. I would recommend you contact the school to be certain.