>>48827388If you've been doing it already, trading it away now would be asking someone to start from the ground up, something that you have already half-completed.
Literally just stick a soothe bell on it and carrry on with your game. It will have evolved within 30/40 minutes for sure. I hatched Happiny and did Happiny-> Chansey-> Blissey in less than half an hour, and before it reached level 20. That was just Soothe bell, follow, and left in my party while I continued playing the game.