Adult Eevee and the baby Eeveelutions

Found a baby sitter I se3

Eevee: Actually, the Eevee up there is future me, surprisingly.
Adult Eevee: It's true!

Umm, how

Eevee and adult Eevee: No idea! *look at each other* Jinx!
Me: Yep. That's future Eevee, alright!

What I don't get is why adult eevee hasn't evolved

Adult Eevee: I ate an everstone by accident!

Adult Eevee: Plus, we already have all 8 Eeveelutions here.

Ahh, makes sense

You remember the Eevee and the baby Eeveelutions meme that I posted before? Well, this is the same thing, but with adult Eevee instead of normal Eevee!