You should join simply for experience, and to try out different styles, so it can influence your style in the long run. As a musician, you shouldn't limit yourself to a certain genre or style, or say I don't listen to this music, therefore I won't play it. If there is a time you don't like what you are doing as a musician, you can always quit. However the experience you'll acquire is valuable to your growth as a musician. Playing in a basement vs playing in public are 2 different animals.

My brother whos a drummer played in 3 bands, and their styles were totally different, one was a latin rock band, the other was an indie/shoegaze band, and the 3rd band he's in now, I can't describe the style, it's pretty unique, like rock/goa. Crazy shit. He isn't truly a fan of those styles, but my brother is able to jam with anyone, with any style.

The best bands won't limit themselves to a certain way of playing, and won't limit themselves to what kind of music they listen to. Just keep that in mind as you play with this band.