How can I self examine myself to see if my liver is enlarged... I'm 19, and I'm scared I might have hepatitis?

Not possible. Sorry, but there is an abdominal muscle reflex that makes it highly unlikely that you will be able to feel your own liver. I do applaud the effort, though. Hepatitis will cause liver damage. If symptomatic, you may notice yellowing of the skin and mucus membranes, abdominal pain and maybe water retention or poor blood clotting. A blood test is required for diagnosis. Good luck!
No good way to. Examine yourself. Feeling for the liver or the edge of the liver, is a skill that you have to be trained to do. Your best bet is to see your doctor to address your concerns. Otherwise you may mistaken think you feel an enlarged liver and unnecessarily drive up your anxiety for no reason. Best of luck and don't fear seeing your doctor.