You are right. My older daughter kept late hours it was not an issue.
It does not sound so bad on the page, but there is so much more to it. Lack of sleep leads my middle daughter to short temper, short words, disorganization, not paying attention in school, forgetting assignments and important dates and then emotional melt downs. etc. etc.
It would be fine if the whole house was not disrupted by the issue on a routine basis.
But it's OK. We will figure out what works for her!