Rodrick was mainly in charge of who was let into the band, and his friends have been talking about a new girl with... pretty sick vocals. They'd heard of her through the school talent show, being a side vocalist due to her 'extremist' voice-- and this new girl just happened to be you.
This voice checked out perfectly with their genre of music, and of course they didn't turn the opportunity down. I mean, they could use at least one girl, maybe just so they wouldn't look like losers.
So there you sat, staring at the band as they evaluated you even though they were gonna immediately accept the moment you agreed. You noticed Mackie, their guitarist, eyeing the case you held on the chair. A guitar case, which peaked the attention of the other members.
"You play?" Asked Rodrick, leaning back on the couch.