What kind of Sig was it? A lot of suggestions may nor be worth spit if it's a comparable piece, I'm assuming it's a Mosquito, but Sig used to have some other .22 caliber pistols as well as current conversion kits.
Was she shooting double action? If so did she try it single action?
Give her small hands, and issue with what is probably a Mosquito firing double action I'd be inclined to suggest a Ruger Mk III or 22/45 as they're going to have a small grip and be single action pistols with a lighter pull. I'd probably opt for the MKIII.
If she gets to the point where she wants to start carrying, I'd opt for a re-issue of the Colt Mustang in .380 once they become available again or possibly a Springfield EMP in 9mm. All of those are going to have small grip circumferences and lighter trigger pulls.