Idea that I had was basically a telekinetic who's powers caused a quite strong atomic wind. So basically, she's POTENTIALLY incredibly powerful, but if she exerts too much force, it starts tearing at her flesh as though she was standing in a sandstorm. The more force she uses, the harder it rips at her. So in theory, she could perform biblical feats with this ability, but it would strip her to her bones and kill her in moments, so she has an extremely good reason to hold back. She'd probably have some bandages on at all times, and carry more with her, just as a result of periodically over-exerting her power in day-to-day tasks. Lifting things up to what she could roughly lift via muscle power would cause at most superficial wounds, like sandpaper dragged over the skin, but as things got heavier than a normal person could lift it would quickly escalate to "falling on barnacles", "getting hit by a shotgun blast in slow motion", and eventually "standing in front of an industrial sand blaster".
Wouldn't fit too well if you were going for a more light-hearted tone, so if that's the case I'll just dodge out. I'd picture her as probably being one of the older members of this group, possibly a survivor of the early days of these abilities beginning to show. Might even have a position like a teacher's aid or something, I kinda picture her in her early twenties.