So, as someone who's been making games as a hobbyist for a while now, I'll give you a bit of my experience (and just what I've seen around).
Firstly, making an MMO - While I respect the idea, realize it will be
significantly harder than making almost any other kind of game. It'll be an interesting venture, and you'll learn a lot, but it will be difficult. If you and your team are incredibly dedicated and sufficiently skilled in networking and the like, you may be able to come out with a project, but it will take time and money. It won't be easy. Also (unless you do something truly unique), it won't be able to compete with a lot of the MMOs out there already. They're very well established, and most of the MMO fan base is pretty well dug into whichever game they like best. Do not dive into an MMO as your first game, and don't expect to sell any copies. Try a few single player ones first, just to get a feel for it all.
As for just generally "Can I make it as an Indie?" Well... sorta. It depends on your definition of
making it, really. There are
a lot of indies out there. I know a few personally. It's hard to get noticed, and once you do - it's hard to keep an audience. The big success stories you hear are pretty rare, it's a bit like winning the lottery. For most indies, "making it" means getting enough revenue to either fund your next game, or to convince a publisher that they should fund it.
In short, here's a set of blunt truths:
- If you don't know what Steam is, you have some work to do just getting familiar with the industry.
- Start with simple, not an MMO, it's very ambitious and there's a good chance you'll get frustrated and never finish.
- Don't expect to get some life changing amount of success from it. Making it in the gaming world requires a whole lot of stars to align, and more often than not you simply won't get noticed.
I don't want to deter you - you never know where the next great game lies, maybe it's yours. You know what you're capable of, and there's no harm in trying. Making games can be absolutely wonderful. Go for it, have fun! Just don't quit your day job.