The tariff for a four year sentence means that he would have had to serve a minimum of 3 years before being able to apply for parole. A sentence of less than four years means you automatically get released after serving 50% of your time.
He would have been sent to an Adult prison with a wing that specialises in sex offences. He would also have been placed on the sex offenders register for life, which would make it nearly impossible to get a job, and have a normal family life.
She is only going to serve 3 months and that's it.