[Should she tell this new person? ...well, she already agreed to join her 'Crew' so she should.]

Not everyone is an Allomancer, no. Only a few are, and almost all have noble blood.

[A small pause.] I'm a Mistborn; I can burn all Allomantic metals. Mistings can only burn one and they have names based on the metal, what they do, or both. Tineyes, Pewterarms or Thugs, Coinshots, Lurchers, Seekers, Smokers, Soothers, and Rioters are all names for Mistings.