I used to revise from 12am-3-4am for a levels lol.
I found it a good time to revise because no ones and nothing is awake to distract you. Obviously only do this on days where you don't have an exam or college the next day, get a good sleep the day before exams.
It’s not bad at all, during gcses I used to wake up at around 4/5am before school to begin studies. My evenings were too jam packed because I had a nurse come round to help with a few things. It’s whatever suits the individual