Making an MMO is far out-of-scope for a beginner. You are correct in thinking that you won't be able to reasonably handle the workload for producing something that large. It also involves far more overhead, bug-checking, and sheer content.
Your best hope is to scale back your scope. Boil it down to the essentials of what you want to make, and cut it back to the bare minimum. If you want to make an MMO, start off by making a very stripped-down adventure game that employs the mechanics that you would eventually want in your MMO. Cook up the basics of characters moving around and interacting with things, but do it on a single computer, with just one player. Start off with one, small environment. Refine those mechanics and interactions, and get them feeling good. Produce a small-scale amount of content that you can be happy with, maybe a few minor quests for your player to follow. At that point, you will have a game, a lot more experience, and possibly a beginning point for your MMO.
From that point, you can start experimenting with scaling things up. Add a second environment. Start trying to add a second player that can be controlled over the local network. Dial things up at a reasonable pace, while learning what is needed.
