The first thing to decide is if you want to do your game by using a general purpose engine or something specifically designed for rpg's. Realm Crafter would fall into the second category and would probably be a decent choice to gain experience if it's nearly free, but I would recommend googling "rpg engine" and check out however many there are around. It would be better to find a free engine or one which is very inexpensive as you can consider it a stepping stone more than anything. Another choice would be to get an rpg game that has an editor and do a mod.
The engine would need networking if you want to play with your friends. It's better to just connect peer to peer to avoid the expense of a server, so see if it has multi-player functionality. If you can use models that come with the engine you are going to be off to a good start, because games take a lot of models and modeling is a skill that can take years to achieve, and even if you are a good modeler, a game like an rpg could take a long time to do all the models. If you are serious about game making, you should also look into a modeler like Blender so you are learning both skills at the same time. Blender has a pretty nice general purpose engine built in also, that you might want to take a look at.
On the other hand, if you want to go general purpose, then you need to start by learning a language like Python. Actually, no matter which choice you make, I would recommend learning Python first. The place to start game making is by writing text guessing games, etc, after learning the basics of the language. RPG's were originally written in text and that's also a good way to start learning. Once you understand program flow, etc, then it's time to move into graphics. The games you write at first should be very short, but complete.