Is it normal to want to quit a team even though you're good

well, i'm part of the school soccer team... i play goalkeeper for them.
problem is, i never wanted to play at that position. only chose to play as keeper cuz when i was in the first year, they needed a keeper and i was pretty good. and i also wanted to get into the team, so i joined on impulse.
now, im not boasting, but i'm the best they've got and the next is far from me. but i'm slowly losing interest in playin soccer for the team cuz i don't want to play as keeper, and they refuse to let me play elsewhere... and i'm considering quitting
don't get me wrong, i love my team, i'm the vice captain. but in this situation, i'm not sure what to do. i've been told that i'm selfish, cuz i dun wanna play for them jus cuz i can't get what i want. but nobody really considers the fact that i've been keeping quiet for almost 3 years already, that maybe i can actually perform as well in another position...
so what do i do now?