ELI5, why is going to bed super late bad for you if you still get the same amount of sleep?

Question

I’ve always wondered this, espeically over summer break or for those who work later but why is going to bed late bad for you if you still get the perfect amount of sleep?

For example, last night I wen’t to bed at like 1:30 AM and woke up at 10:30 am, which is 9 hours? So if I’m getting required sleep, how is it bad for me?

In: 2565

Answer 1

I needed your example to understand what your asking. It makes no difference what time you go to bed. Sleeping 2-10 is the same no matter am or pm.
This is probably some silliness adults told you as you were growing up.