Well, opinions vary. Pretty much every make-up expert I have heard from, however, has the opinion that blue eyeshadow is something that shouldn't ever be worn, unless you're dressing up into something special for Halloween or a carnival. And I sort of agree with them.
I think your mom looks great -despite- the blue eyeshadow, not -with- it.
But in the end, if everyone did only what is generally considered okay, the world would be a bit boring, wouldn't it? If you really want to wear blue eyeshadow and don't need the approval of people, do it.