I Know its bad to ask a girl their weight.. but My girl and my sister both got the volkol Gotma jr's.
My girlfriend is a intermediate skiier and she goes pretty much everywhere.. and she was looking at full women skis and then I realized that she only weights 115 fully clothed in ski gear and she was well under the 140lbs limit for the jr skis.. So she ended up getting the volkol gotmas jr. and I believe that they are 158cm too so they are pretty long..
My sister on the other hand is a ripper that will ski pow, groomers and ski switch with me.. She is still under 5 foot but she got the gotma jrs as well in the 158cm and she rips them really well.. with the reverse camber of those skis they ski well for the length..
so If you are a fairly small girl I would definatly look at the Jr twin tips out there.. they share the same features as the adult skis but for much cheaper.. my girl and my sis both love there gotmas and they may be something you should look at..