I'm going to ditto a lot of the other comments here. I'm not exactly an "experienced" programmer (about two years on-and-off as a hobby), but I do know that if you don't know any details about your program, you won't be able to write it. Programming is not really something where you can just "wing it", especially if you're doing object-oriented programming. Object-oriented was made like that on purpose, forcing programmers to plan what they're going to do.
I would recommend learning C++, mainly because the only Languages I know much about are C++, Java, and VB. C++ is just plain more powerful than VB, and it's "sexier"
. Java... well, on a list that compared programming Languages to automobiles, IIRC, C++ was a turbo-charged Ferrari, VB was the clunker you ditched as soon as you got $2,500 to get a decent used car, and Java was an All-Terrain, Very Slow Vehicle. Plus you could get help in lots of places in learning C++.
After you spend about a year learning and practicing C++ (including how to do graphics, basic AI, standard game loop, etc.), come back to your game idea, and develop it. A lot. Make all the rules, as stated by Alpha Kodiak. Find a friend that doesn't know about your plans for the game (would be nice if the friend knew how to program, and even nicer if the friend is a she and you give me her number...
. If they ask for more details about how something works, you don't have enough details in that area, so keep developing.
Once you've developed all the rules, in the case of object-oriented Languages, plan out your classes. You'll be very glad at this point that you developed throroughly. If you didn't, planning your classes will be difficult, and if planning your classes is difficult, you didn't develop enough. Find more friends to look at your ideas. Find strangers to look at your ideas. Find anyone.
Once you've developed the rules and planned your classes, you begin programming. If you have anyone helping you, it is really nice to have well planned classes, because you can divvy up programming the classes, and make things much easier. Since each class has it's internals mapped out pretty good, you can be reasonably sure that everything will click together with minimal work in the end.
Now with all that, you can see that making a game of SE4's magnitude is really quite difficult. I'm really amazed that Aaron made SE4 on his own, albeit with a large idea factory made up of fans of SE3. Even if all this seems discouraging, I urge you to look into it. Even if the game itself doesn't make it to something close to a working computer game, you will learn a lot of skills that are very valuable in the world today. And you just might come up with a better game idea, and since you've already gone through the process once, the second time around will be much easier (I'm sure Aaron could verify this, or any of the programmers of the other games Shrapnel publishes).
Good luck