What time did the woman go to bed?

Man Why are you so tired? Did you go to sleep late last night?
Woman I got to bed by a little past eleven, but then I had to get up at four. So I only got five hours of sleep instead of my usual eight. That’s not enough for me.
Man No, that wouldn’t be enough for me, either. Why did you get up so early? Were you getting ready for a trip or something?
Woman No, I wanted to get to the office early because I had some extra work to finish. Even though it means getting up in the dark, I’d rather do that than stay at the office until late at night.