There are certain Pokémon that will stop learning moves once you evolve them, so with those, it would definitely be best to wait, but in your Scyther's case, it would actually be better to evolve it early on because its evolved form can learn moves that Scyther can't learn. Other than those few extra moves, its movepool is basically the same, so there really aren't any repercussions at all.

However, I don't believe there's a PC in New Bark Town, so you'll have to head over to the next town, Cherrygrove. Once you get there, just head into the building with the red roof and you'll find a PC in there.

Oh, and I'll need your name so I know who I'm sending it to.