[Mabel's eyes light up as she gasps a little.]

I would love to join your party!! What other classes are there? Can I be a princess? Or an assassin?

[She is so excited by this prospect. Her face is nothing by child-like glee.]

If you say so! I still don't mind. Is Garrus a friend of yours?

[Because that sounds like the kind of 'yeah we're best friends so I'm going to kick your butt' thing she gives Dipper.]