If I go to bed late (eg. 2am) and get up late (eg. 11am) - effectively getting 9 hours sleep...
Does that matter at all?
I know its preferable to go to bed early and get up early....but i find it kinda difficult because im doing a masters course which I attend at night from 6pm to 10pm so i get home and only have time to eat ...then do some home work....then late to bed!
as long as you are getting at least 8 hours your cool. if you dont feel grogy during the day than it is cool. if you feel tired it may be effecting you. its the amount more than time of the day i think