Should I quit guitar :/?

When my guitar teacher tells me how to do something, I understand, but when I go home I completely forget. I don't know how to the practice without asking for help. When I look up lessons on how to do the things we practiced, I don;t understand. And I keep forgetting to practice guitar too! I want to play, but I know I'll never be as good as Angus Young or Jimi Hendrix. Heck, I don't even think I'll be a good rhythym guitarist! Ahhh. I want to focus on piano and singing, but I don't know if I should get rid of guitar