If I wanted to recreate my childhood game Pokemon Red/Blue/Yellow for GBC, what programing languages should I be learning?

Question

I want to develop an RPG game from the past because nostalgia :D

Answer 1

You should learn the one that is easiest for you to learn first. Seriously. Don't jump to C++ because you are "supposed to." Any good programmer knows multiple languages.

Instead, find one that is easy and cheap to get started in. One that is free and sololearn provide all language for free.
High-level languages will work best for a beginner. I would try things like

Gamemaker
Monkeycoder
Flash
One of the Lua ones that has a graphics lib already
Python with a graphics lib
A BASIC variant like DarkBASIC, BlitzMax, whatever

Remember, you first game is going to be something like Hangman, Pong, guess the number. Not Uncharted.

Many of your game development heroes learned with MS BASIC.

Answer 2

The easiest way is to use the RPG MAKER (XP for example) with Pokémon Essentials (from pokemonessentials.wikia.com/ ).
This is an almost complete library that takes the complicated part for you.
It is written in Ruby so perfect for a sololearner. :))