You don't really get older when you stay up late. But you can start getting wrinkles and bags on the eyes from not getting enough sleep.
I actually hear somewhere when you don't get the required amount of sleep you lose some time off your life and can die sooner.
You can also die eventually if you don't sleep at all. Sleep is very important to our bodies and our health.
Getting enough sleep at night helps us function in the day. When we don't get enough sleep we're not very alert and can get into accidents. And even fall asleep while driving.