For this kind of thing CG is right.
Lots of people try to code MMOs and find they fail because what they're trying to take on is often much bigger than themselves. MMOs require a lot of skill, a lot of organisation, a lot of management, a lot of content and a lot of work. Whilst it is a possibility, even for a small team, but for a small team they really need to set themselves some realistic goals. It's easy to get overly ambitious, I am guilty of that myself, but you've got to level your ambition with realism and that doesn't necessarily mean erase your goals, perhaps put them away until you've got more behind you.
You've finished a project in FPSC and worked hard and no doubt you're proud of the result because it is an achievement. As somebody who has been pretty ambitious with project ideas and trying to execute them, I would say you need to approach it with realism. Your skills, your time, the time of anybody else you have and their skills and of course your own timeline. My project 'Ronin' would be massive and as much as I want to work on it, I should actually finish the much smaller, 'Abeyance'.
There's nothing to say you can't work on smaller similar projects to build up to it, that might be a good way, but of course you'll find what works best for you and this is advice from a friendly forumer. I think I'd rather see you come out with another project you're proud with (and if with something like UDK, even better, because it's a nice start on the professional path) than one that could potentially become too big and find it's not manageable.
I'd say try learning more UDK and I'm sure you'll be able to assess your own skills more and see how big of a project it would be.
Food for thought at least.
