How to get my sister to let me use the TV?

Ok, so, my mom decided that during the summer me and my sister swap between getting the tv each day. She doesn't even use the tv on her days and I have games I want to play with my friends. The only reason she complained about the tv was because one day I did a speed run of Sonic 3 and Knuckles and it took 3 hours. I told her she could use the tv all morning since I stay in bed and use my phone. On my days of tv I let her use the tv in the morning but on her days she says no and shoots me with the nerf gun. I asked my mom and she said if she doesn't want to use the tv I can't either since it's her day. Please help!