I'd say anything in a 9mm would work for her. The recoil is minimal. I personally like the M&P compact or the Beretta PX4 storm sub compact.
To demonstrate the recoil here's my wife shooting her P99AS one handed. Granted this is a full size pistol but it's also one handed. She's pretty tiny too.
*edit* sorry for the crappy quality, I shot it on my phone