I started my son out about a month after he turned two years old. I used a Henry Mini-Bolt. It's a single shot bolt action very similar in size to the Crickett or Chipmunk. It wasn't until this year, he is five now, that he has been able to really shoulder it properly due to it's size, and he is tall/has long arms for his age. The levers will probably be to long for her for quite a while. He has a Henry lever 17 HMR that I got him for Christmas. Still too long for him, but he does good at the bench with sand bags and he will grow into it. He also likes my 10-22 really well, so I have been thinking about a youth model. Took him shooting today. He shot the 243 that I got him for Pre-school graduation for the first time. He had a blast. The recoil didn't bother him.
You will need to start with something small that will fit her size. Just keep in mind that a small gun will be like shoes and clothes, she will outgrow it quickly.