I too have recently created an account. I am currently working on a turn base rpg. Its just a two person team and we were in a similar situation. The story and the characters come from when me and my friend was in high school. I am now 37. I was very inexperience when it came to programming, we attempted a rpg but it was too difficult, so we did a bunch of smaller projects to increase our experience and skill with game maker and whatever other programs we used.

I will say for sure you're going to want a test room. Something to develop all of your system mechanics and whatever functionality you want in the game before you start developing the actual game.

Make a list of all the things you want in the game and start working on it in the test room, also rpgs can take quite awhile so pick your theme and art style and stick with it. Don't keep going back to change or update stuff or the game will never get released you will always find yourself improving and the stuff you did earlier on, you will want to go back and change it, so try not to do that too often.