Well now, 4:30 in the morning is there something bothering you: or maybe ur mind and body are not really working together like they should. It's not a problem as in medical help. But u should tell your doctor and if it keeps bothering you ask for a ( sleep test). So the doctors can see how you sleep and tell what's going on, how and why, you wake up so early.
It could be that something is on your mind or you feel that you may over sleep and be late for something. It could also be the tine you go to bed maybe you are getting enough sleep and that is your bodies way of telling you. You could talk to a doctor to see if there is a more serious cause.