Can I arrive before my Germans student visa starts ?
Best you clarify with the visa issuing consulate or embassy. A student should always arrive before classes start so they can get prepared and settle in. But you should have thought of this before applying. Unless they can change the date or give some kind of accompanying document to give permission, then the visa will not allow you in. Not only would it make problems at German immigration/customs but if properly scrutinized, the airlines wont allow you to fly. And you would not get your flight ticket refunded for not having had the proper travel allowance.