Apparently the old adage that an hour of sleep before midnight is worth three after is correct and it because the SWS or Slow-Wave Sleep occurs in the first few hours of sleep. Some research suggest that this will happen no matter what time you get to bed, however most people get to bed before midnight which backs up the adage. https://www.sleepio.com/blog/2014/04/22/sleep-fact-or-sleep-fiction/
The interesting thing about before midnight as part of a healthy sleep protocol is that it fits with an ancient and not so ancient strategy used today in Ayurveda. There are three cycles to the day and the 10pm-2am cycle (repeated every 12 hours) is the Pitta time and is when the metabolism begins to heat up in order to fulfil the deep sleep cleansing program. The body literally 'burns' away the toxins and debri from the day and also rebuilds. This is also the time when deep consolidation of memory is done.
So, getting to be around 10 pm will put you good stead for having a very deep sleep for longer and at the same time helping you body to do its daily maintenance more satisfactorily.
Sleep is essential for health and wellbeing and of course if our general health and wellbeing are taken care of we feel better and may indeed even look a little younger.