my eldest daughter is at 4-10" and under 90lbs, quite lean and was fortunate (at the detriment of our check book) to take have classes at steamboat for her skiing career, now skiing blacks and moguls ... perhaps not the fastest less on groomed.
anyhow, i just checked her last yr ski, junior atomic rc8 (?) they are at 130cm. they can (for this yr) be longer, but a set of elan black pearls at 144 seems a bit long. she loves her atomic 8s and they were a good deal at ~$220 w/atomic bindings. she noted she would ski these now, they reach just over the chin in socks. her, not the skis
she also loved the previous yrs elan RCS for kids, they had salomon 305's, they move to my next daughter for this yr, their at 120cm.
anyhow, IMHO i think any ski with a kids (or light womens) flex in the 136-140 range that 'she' picks would work great. longer perhaps for an extra yr of use if she's good. (my daughter is somewhere around a 'steamboat' 7-8, blacks, mogels and mid powder?) my younger daughter while 3-4 inches shorter skied 110's last yr as she hasn't quite the natural balance (my side) as my older. the shorter helped prevent the previous 2 yrs of 'mis-haps'.
anyhow, the comment on 'her' pick is that it seems, unless she's in competition, the kids i know with ski's like them if they pick them ... yeah, maybe a shops guidance, but overall, if they pick em, they love em.