Is it normal to stay up all late regularly?

Okay maybe this is a stupid question. Maybe this is because I had my first ever try at coffee 10 hours ago. But really. It's 7:30AM the sun is already coming up and I still haven't slept and I'm not even tired. For the past few months I have been going to bed at around 3 - 5 AM. I thought I would be able to make a curfew for midnight when school started, but it just ain't happening. I wake up at around noon every day, which isn't a problem since I don't have morning classes. I've always thought of myself as a night person because I do my best brainstorming late at night. I've pulled several all-nighters doing homework and I don't feel too tired to last the rest of the day--in fact, I stay up late until at least 3 again. I know it's bad for my health in the long run, but I can't seem to help it! IIN?

Also I might add, I decide its absolutely time to sleep when I start to feel hungry. Either that or I go eat what I'm craving, whether it be doughnuts, chicken wings, or just about anything, haha (and don't worry, I'm probably underweight). And I've gone to sleep with my sister's insane army of deafening alarms blaring from her room...