Actually it is all about our comfort zone. If we are comfortable in morning study we should try to wake up early and start our study. But some students not able to wake up early. Then on behalf o my experience they should follow the night study routine.
There are many reasons like if we force ourselves to study then we can’t focus on our study and this will not be fruitful for us.
So according to me we should make our routine ourselves the because until we enjoy our study we can not learn anything.