Oh ho! Someone trying the same idea I had! Here's my only advice to you: GOOD LUCK!
No, I'm not joking. Good luck. Ten minutes into trying to program it and you'll realize why AAA titles and Indie Developers do not attempt to do it. The first reason is that it's a large, cumbersome, complicated mess that requires craploads of notes for even 2 hours of gameplay.
So, let me see if I can help you out by pointing out the areas I had issues with:
1. Create all your stories and branches on paper BEFORE ever programming a thing. I am not kidding, the programming, mapping, Database, everything else is much easier if you get your story, your branches, your characters, and everything else out of the way first. Do not even open your program before doing this, or you will be spending a lot of time doing "rewrites" and "reworks" of characters, areas, NPCs, systems, and even your story more than you'll be actually making your game.
2. Have a design plan right out of the gate. What systems you use and how you tackle things like stats, weapons, armors, battle, and even choices are important. These are so important that right after you do the story, you should work on this. You will avoid a lot of my pitfalls if you do. By "Pitfalls", I mean having to rework the database a bajillion times, having to reorganize things within the maker, having to delete or omit systems because they didn't pan out or didn't work as you wanted them to, and reworking how skills, items, or weapons/armors work.
3. Realize that there's no shame in limiting the amount of choices and "paths" in the game. It becomes easier on you if you do limit some of these paths. Trust me on this one. Nobody is going to give you points for "trying" to create that kind of game. They only give you points if you can pull it off... and even then, only if you pull it off in an "above average" manner. Right now, I have so many paths and choices that it's quite literally a nightmare.
4. Before you commit to any kind of system, make sure you can actually do what you want it to do. If you plan something and there's no way to execute it with the engine (or with current scripts), then you'll have to rework the system or drop it altogether. Make sure you know what your options are here, in case something does not work out as intended.
Beyond all of that... I don't think I can really offer you any more help. Whether you make it or not is really up to how much ambition and time you have for the project. A project like this requires a lot of time and a steady stream of ambition.