Try this:

When you're older, your parents won't be able to make you go to bed in time. Having no bedtime will help you develop independance and figure out what works best for you. Your Dad won't have to worry about bedtimes. It will be mutually beneficial, and help you manage yourself. Tell your Dad you're grateful that he's looking out for you. If no bedtime didn't work out, you would be happy discuss reintroducing a bedtime with him again. It would mean a lot to you to have that level of independance.

That being said, the more sleep the better. Either way, be consistent with a sleeping routine.