Yes, you should be evolving soon...

[She pauses, and her ears perk up as she studies him a little more intensely.]

Actually, you probably should have evolved a while ago, and I don't think you need a stone... but you're having trouble with it? That is very strange.

[Mightyena shifts her weight as she thinks it over, looking increasingly troubled.]

You should speak to Dr. Denne about it, if you don't evolve soon. Or... I can speak to him for you, if you'd like.