Well, I'm in my 70s now and boy, how things have changed. Even a few years ago, when I was in my 60's, my normal bedtime was no earlier than midnight. I have always been a 'night owl'. It wasn't unusual for me to stay awake till 2am, reading. Now, I'm lucky to be wide awake at 10pm! Sometimes--since I now seem to wake up by 7am--I'm feeling sleepy by 9pm.
According to my generic version of FitBit, I got 9 hrs and 5 minutes of sleep last night, waking up about 10 minutes to 7. Yes, that includes getting up 2-3 times for the bathroom. But most of the time, I'm able to get back to sleep fairly quickly. One night this past week, I was very involved in some computer 'things', and I actually didn't get to sleep till 11:30pm! But that's unusual now. I still 'need' my 9 hours of sleep most of the time; that's been my normal for a very long time. My 'bedtime' has just changed.