Can I make an adult immortal?

I was planning on waiting until my herbalist was old to make him immortal, but turns out adult wolves don't appear as an option with the jellyfish. Does that mean I can not make him immortal? Or am I just in a few rollovers?

Because I also can't sell adult wolves but there's a bunch of females in heat at the TC :/ 

You can't make him immortal when he still has it's role as a herbalist, i think

ah thanks 😅😅 i didnt notice