Assembly is easy. (And the better grades — Real Grade, Master Grade, Perfect Grade — look good after simple assembly because they're so well designed. Especially the RG 2.0 that she did first. It's brand new, I'm still trying to get one for myself.)
Etching (i.e., custom panel lines), painting, and decals, on the other hand…
If she makes an attempt at those, then we'll know she's hooked.