Pokésav and creating a Mew 3

[Mew_3]

Greetings from a 'somewhat techie' dad. My son is 10 years old and has a Nintendo DSi with Soul Silver, Diamond and Pearl, and Platinum. He desperately wants to create a Mew 3 character / Pokémon sprite. Has has a DSi Action Replay cartridge and USB cable, and we have downloaded Pokésav. Upon reading the FAQ, I'm confused. A lot of this stuff is over my head. I want to help him out, but unsure how to get an editable file from the game or Action Replay cartridge into Pokésav. I don't want to screw up his game just to try to create a custom character.

Question for the experts ... is 10 years old way too young to be messing around with this stuff? He's on the cusp of understanding a lot of this and through YouTube is finding out about all kinds of customization. He really wants to do it but I'm afraid a lot of this is over my head.

Any feedback appreciated. He is obsessing over Mew 3! LOL.