It's okay. His personality's purity level was around 3 years old anyway. I'm sure he'll adapt to this just fine.
"It won't kill me and I can get mana? DOWN THE HATCH!"
Personally, my biggest regret is that he came here alone. I would've loved to see Shota Ash interact with the various girls.
Oh hey. Also, now that he's physically 3, maybe it'll actually be a fair fight for the Earth Demon Lord.