A better system is to only get in bed when you feel sleepy, like you could fall asleep in the next 10 minutes, and wake up at the same time every day. If you get in bed and don't fall asleep in the next ten minutes, get up and don't come back to bed until you feel sleepy again. Strongly associate the environment of a bedroom with sleeping.

Forcing yourself to get in bed even when you're not sleepy can potentially lead to just lying there thinking, conditioning yourself negatively, especially if the character of those thoughts is "argh I should be asleep why am I not sleepy I'm going to be so tired in the morning what's wrong with me..."