Is sleeping a waste of time?

Instead of sleeping at 11 like im supposed to i stay up till 2/3pm and study, learn korean/chinese, read books, watch music videos, and than i sleep for 3/4 hours and wakeup at 6

i mean the time i spend sleeping i could be doing someting productive..right?
Update: but i can function with 3-4 hours of sleep

im 14 btw
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