Are you into exercising? If so, you could try going to the gym, a run or anything else about two hours before bed. Hopefully, it will tire you out before you have to sleep. Also, get a light filter for your phone to stop the interruption of your naural sleep cycle. As someone else said, try mediaion before sleeping. Dim the lights, have a horlicks, read, just trying to relax is the main thing.
I tend to stay up late, it's natural at this age, due to our sleep cycle getting later on. Try not to worry about it too much.
Good luck.