Agree with DJ,
Something along the lines of a Fanatic Diamond 9.6 @ 150lt is a great starter for her weight. Based on their Fly with low rocker and easy balance. It's good on flat water and introduction to surf. Atlantis and Naish probably have similar dimension boards which would be comparable. Check out the Seabreeze buy and sell or even your local sup stores for second hand equipment (often hardly used and big savings)
My girl learnt on the Diamond before moving on to a 9ft Stylemaster at 115lts.
If she gets into it, she will progress to narrower and lower litres quite quickly. Depends if she's a weekend warrior or becomes addicted, but no point making it difficult at the start.
enjoy the ride