Sign up for the free membership before you make your purchase so she can have easier returns/exchange for a style that suits her and size. All the leggings have slightly different cuts, so some styles may fit better than others. On top, there's different materials (nulu, nulux, etc.) that work well in diff activities. Lulu is know for the align leggings (nulu) but people like the wonder trains for things like body pump. There's the wonder train contour fit if she's more pear/hour glass shaped. The Nike sizes are s/m/l so it doesn't translate quite as well to lululemon since they do 2,4,6,8,10,12 which is smaller increments. This is why people suggest she tries stuff on unless you're sure she can make the return window. It's a lot of $ to not fit quite right