I get up at 3 am and sleep at 9:30 pm. What is the best time for me to meditate?
Best time to meditate is when it works best FOR YOU!
Early morning hours are wonderful if you can be awake and go deep. This is because all around you most people are sleeping and there is a pyschic stillness not found at other times during the day.
That may mean getting up earlier, so this may not work for you.
Does your work schedule permit a "meditation break?"
When you come home from work, does your family or home life permit you to meditate before dinner?
Can you meditate before going to sleep?
While not a substitute for sitting meditation, bring your meditative intention into your work and daily activities: by inward chanting, mindfulness, quick breath or mantra breaks during the day.