I've been trying to go to sleep at 7pm for the past few weeks and never successful. is it just biologically impossible? i want to wake up at 2am.

Gradually move back : This is especially difficulty if you are a "natural night owl", but even regular 10PM sleepers would find this difficult. You need to move back an hour at a time, kind of like changing time zones. So to bed at 9PM x 2-3 nights, then 8 then 7. Minimize exposure to blue wave light - it's found in back lights of LEDs and other digital screens. And last meal of the day is at least 2 hours prior to bed