There is no direct evolution line into Mr. Mime or Mr. Mime ex from Mime Jr. (the fact that there is no English-language Mime Jr. card notwithstanding). The reason Baby Evolution is on the baby cards is because that is the correct wording that allows you to "evolve" the babies.
Give it Baby Evolution, and change the text so it says "...put Mr. Mime or Mr. Mime ex onto Mime Jr. ..." rather than just "...put Mr. Mime on Mime Jr. ..."
Also, it's horribly bland. How many baby cards out there are that boring, even the old ones? None of them, that's how many. At least make it do something... as it stands, there's no reason to have a card like this in your deck.