well it depends cause if your looking for a really flexy ski u can go with something like the fugitive or some other park ski. If ur looking to do some outside of the park skiing try the ar5's and sick because u can ride them all around. The 1080 is also a good started ski. I ski the 1080 and last season was my first on twin tips
Try to fine a ski around 160, and a light ski would be best for you. Since your so thin, look into Line 1260's if your on a tight budget, or Salomon thrusters.