I was thinking that I really wanted an actual little teenager (ie not a 19 year old who barely counts) and then I remembered that I had one with a perm account sitting around just waiting to be picked up again, because she is the greatest, or possibly the worst. Her full name is María Aracely Josefina Penalba de las Heras but she goes by Aracely and her superhero name is Hummingbird. She remembers absolutely nothing earlier than a year or so ago when she was rescued by Kaine Parker aka the Scarlet Spider, one of Peter's clones who got all the surliness and grumpiness and magnified it by at least a factor of ten. She's assumed to be the reincarnation of the Aztec god Huitzilopochtli and she's a very powerful telepath/empath who can cause overwhelming fear in people as well as a bunch of other random stuff like floating and turning into holy fire to smite demons and having the metabolism of a hummingbird - constantly eating, constantly talking, extremely hyperactive. Oh, and I can't remember if it's relevant to anyone but she's invulnerable to other psychics - if you try to read her mind her brain sends out an attack signal that causes intense pain to all telepaths in the vicinity. It's not good.
She's 15 so she needs a guardian. Storm votes 'not it' because they met once when Kaine and Aracely had to kill Wolverine for the Guild of Assassins (lol) and Storm just absolutely cannot with her.