I dunno if 10 years on the registry is as light as the headline makes it seem. It's a bit more than a slap on the wrist, even without the other requirements of the sentence.
Frankly, it isn't a case where jail time is the appropriate response. Mandatory treatment, supervision, registration, that's right where out should be for this instance. She's not likely to be a threat to other kids, so sentencing needs to be focused on ensuring that rather than arbitrary punishment.