I've made my own Final Fantasy VI-alike game engine. (Some screenshots:
http://i139.photobucket.com/albums/q316/exseiken/Mon%20RPG/fight.jpg,
http://i139.photobucket.com/albums/q316/exseiken/Mon%20RPG/world_map.jpg,
http://i139.photobucket.com/albums/q316/exseiken/Mon%20RPG/screenshot9.jpg
Most graphics assets are RPG Maker graphics I borrowed.)
Making a game engine for a 2D RPG is totally doable on your own, however you are going to be working on it for a long time before seeing results. When I built that game engine, it didn't take me an eternity but I had no job, no school and no lover so I could afford to work on that project from 10 AM to 3 AM if I wanted to. And I also had an unending love for old-school Final Fantasy games. I could never afford to do that now at 29. I have stayed away from Final Fantasy since they turned bad, and it gave me an idea for a new battle system that would be (IMHO) a lot more fun and tactical than this ATB that I copied, plus a new skill system, item system, etc. but I just don't have the time to work on it. I wish I had the time to work on it full time. =/
But I disgress...
I would suggest working on a simpler genre. Unlike most other genres, Japanese-style RPGs like that don't have much physics to deal with, which might make them sound easier to make, but the amount of data that is involved in a RPG is absolutely crazy. You have item data, weapon data, armor data, skill data, enemy data, enemy group data, hero data, shop data. And then you have two major and separate game modes to create: the area map mode where you talk to NPC, open chests and show cutscenes, and the battle mode where you, well, fight monsters. If you want the game engine to have features similar to FFVI, you're going to put a lot of work in both. For example, FFVI had a very extensive battle animation system, where you could of course draw sprites, but also generate vectorial stencils that mask parts of the animation, generate trails for character sprites, animate palettes. So a cheap "missile-with-particle-system" 2D animation system just isn't going to cut it. (Again, assuming you want FFVI-level quality.) I could definitely be wrong, but since this is the "For Beginners" forums I'm assuming that you're not ready for that kind of game. A RPG also involves a very large amount of content, and players chew through that content really fast. It can take me 2 hours to make a cutscene of 5 minutes (which is still a joke compared to the time it takes to make a CG 3D cutscene of 5 minutes...) and a player will typically only see a cutscene once, unless it's before a hard boss or something. My RPG took 2 hours to do from start to where I was at when I left it (when I decided to rework it into something that isn't as much of a FFVI ripoff), but I had probably spent 4 months just creating content. (Not programming or drawing.)
I think a simpler genre would be something like a side scroller. You have a lot more physics to deal with, but you only have one game mode instead of two, much less content to do, less music, probably less assets too (although I could be wrong on that one.)