Although I myself am new to Unity, I am not new to programming or gaming. I say nay. It took me quite a while to learn programming logic. It’s not as easy as it looks, it takes a while before you start going “oh, that’s what that’s for.” I will say though that UniScript does facilitate things a lot and I am going to start making an Asteroids game in a few weeks. I can almost guarantee that I will write it with much less code than it took me in Flash. It still doesn’t make it any easier, programming logic takes a while. On top of that you are also going to learn 3D, which also requires it’s own sort of logic and hands on practice
When you say mid/high level game, that instantly makes your goal unrealistic. You could probably go for a casual game and do a good job there, but when I think mid/high level, I am thinking a decent FPS or a simpler RTS game or what not. The amount of art and programming involved in any of those games is huge for one person to do alone, especially if they are starting from scratch.
Now if your goal were something like Tetris or Asteroids, then I would guarantee you that you will get enough knowledge to get those done in a little over half the time. However, if you were to learn ONLY what you need to be able to make those games, then that time could be shortened even further. It’s not a bad strategy as you could learn getting your hands dirty, not a bad way of doing things.
To give you an idea;
This is an XNA game made by one guy. Supposedly he made it in 6 weeks. However, that dude had massive amounts of experience coming into that game, and that is just one stage. I am sure that if he would’ve needed to make a full game with several stages and multiplayer functionality, it would’ve taken him a lot longer. And again, his experience counts for a lot.
As to recommendations, you don’t have to make a 2D game, you just have to make something that is either a finished game or a polished demo.
The former means you will have to probably do something 2D, a platformer would be an example. The latter could be something a lot more developed like a FPS or RTS but you will probably not be able to get all of the game art needed for a full game so you would just have to make a polished demo with one or two stages.
Finally, use C#. You will thank me later when you learn how incredibly awesome the Microsoft Visual Developer IDE is.
Any other questions, feel free to ask.