Playing stuff that's new to you is always a good thing. Have a great time! Never hurts to expand your repertoire. I'm in a similar situation, working on a new pop-based covers project. Katy Perry, Kelly Clarkson, Orianthi, Adam Lambert... I've never even HEARD some of the songs we're doing until learning them. On top of that, I'm learning 22 CCR songs for a gig coming up in a week and a half. Never thought much of those guys, but this stuff is SO pure and simple, it's a nice contrast to the pop crud. I swear, Have You Ever Seen the Rain is one of the most beautiful songs I've ever played, with a great bassline. AND I recently jumped into the fire with another hard rock cover band, doing revved up versions of GnR, VH, Crue, Poison, Jovi, Whitesnake, as well as a few current things played in that same style. Lots of fun, and lots of gigs!
PS -
Some advice - don't bang the cute chick in the band, it's not smart in terms of band politics and longevity. Use the cute chick's friends and gigs to meet other cute chicks