1. RPG Maker is not something you should use to train for programming, hell at least Scratch gives you the idea of how picky programming is, RPG Maker is a tool to make RPG games, not a programming language. Also if you were programming scripts then it'd be fine, but you're using the 3DS version!
2. No you can't and most likely never, someone made a exploit that got patched and having it only 3DS to PC would be hard to do and kinda dumb without a PC to 3DS option, which would enable exploits. Also they'd have to create software to support the 3DS's editor.
Really you can learn to code in any scenario you're at. Use repl.it if you can't download software or don't have a computer. On your 3DS, get SmileBASIC, you can learn to program in BASIC, and some really cool games are actually made on there, someone made Mario Maker where you can upload your levels since they're a different file, and you can upload files/programs onto SmileBASIC's servers.
Hoped this helped!