I am a terrible singer... will i ever be good?

i am a terrible singer.... i recently joined choir and a couple other singing groups at my school, this summer i want to take singing lessons. i used to be awful at singing now i am just terrible not as bad as i used to be though. i am 14 y/o boy and i am better at hitting higher notes i am a tenor. will i ever be good at singing? is it even possible to change a bad voice? i really enjoy acting but i never get leads or supporting roles becuase my singing isnt good so i really want to work on it but not if i will never get better.