I fell in love with a guy in my drama class but I have girlfriend that I'm dating fir month now I don't know what to do

So for context I'm 16F and I came out as pansexual and honestly I have girlfriend but the more problem is that I'm catching for guy in my drama class that's older than me and is my exact type and I really really like him but I don't want to leave my gf and honestly i don't know what to do can you all help me?