Should I evolve this Mew to Mewtwo or wait for a better one?

What sorcery is this

Hmm, I'd say wait it out. Right now, this one isn't good enough, you don't have the candy anyway, and the evolution becomes cheaper once Mewthree is released.

Nice Photoshop ;)

You don't have enough Porygon candy for your Mew

Not sure why you'd want to evolve Mew to a Porygon, but hey - whatever floats your boat, man. You do you.

Can I get a downgrade? 9 Mewtwo and 0 Mew.

I'd evolve this Mew to Porygon2. I mean you have Upgrades anyway and you get 27 candy for free since you only have 23 Mew candy but evolve for 50 which isn't in red colour. Let's roll.

My god....the stardust

You have to walk Mew as a buddy or else they won't let you evolve it.

There must be a bug with your game as they're asking for Porygon candy to evolve your Mew. :/

You can't get an "above average" Mewtwo, the lowest currently possible is 67%.