Hey, I'm also a beginner with stats similar to yours (although a bit heavier).
I had started my board research with Burton as well, but then found that there are a lot of other great boards to choose from. I am eyeing a K2 Lunatique right now, which I've been told would be great to learn and progress on. It's from last year so should be good deal if you can still find one. Another one to look into would be the GNU B-Nice, people seem to like it and it's also a beginner-friendly board.
And... if I was made of money, I might go for a NS Pandora after seeing how much girls on here who have one LOVE it
NS is kind of out of my budget though and maybe not as beginner-friendly as the others
If you are set on Burton, I will repeat what the others said: the Feather looks good. Demos are your friend too
Do you already have your boots? As the wise ones on this forum say, the boots are way more important than the board. But, moot point if you already found the perfect pair.