>>58687263To make the game itself? Yeah, RPGMaker will work fine. You'd use something like Pokemon Essentials.
If you want finer control, I'd suggest GameMaker. 8.2 is a fanmade continuation of the easier to use classic GameMaker, and has a helpful community. If you want more platforms to be supported though, go use modern GameMaker. It's free to use as well, and while it's not as easy, it's way more up to date and supports more than just Windows.
A Pokemon game is a huge challenge though. I'd recommend making something way smaller first, to warm yourself up. At the very least, start small. Don't make a whole new region, you'll burn yourself out. Make a game that takes place in just a town and work from there.