Hi I am parth and am 12 years old.I wanted to ask that weather unity 3d is easy enough for me and my game making team???the smallest is 10 and biggest 13.and if not what shall i use for now??
Are you wanting to make a specific type of game (first-person shooter, role-playing game, etc.)? If so, then you may want to find out if there is a game engine that helps you build the specific type of game that you want to build (RPG Maker for a role-playing game, for instance).
If you’re wanting to make all kinds of games, there are other options out there. My first game-making experiences at your age was with a program called “The Games Factory” from Clickteam.com. It isn’t as powerful as Unity, but it did help me understand some game concepts without needing to program.
Whatever you’re planning to make, start simple. Ridiculously simple. If you start with an extremely complex game, you’ll never finish it.
I’m thirteen years old and it works pretty well for me. There are plenty of tutorials online about coding and Unity in general. Heres one really good site with almost 130 tutorials compiled in the same place. Unity Magic
Go do some tutorials for some basic game you think look nice, then that will answer your questions. But yes, to start off, it can be easy… but to master it… it can take many many years.
I think it depends.
For game development, Unity is the best tool I’ve found. It’s easy to get started but you need to understand how to program first.
If you’ve never coded anything before, I’d suggest spending some time on http://www.codecademy.com to get a pretty good intro to javascript.
Then once you’re comfortable programming, check out the unity tutorials:
http://unity3d.com/support/resources/tutorials/
(I’d especially focus on the 3d platform tutorial, because it gives a great overview of Unity as well as telling you what to do)
As Patrick said, if you know some programming Unity is lovely. It does a lot for you, though that might also make it hard. So if you already know a bit what you’re doing, unity will make it much easier and fun.
On the other hand, if you’re just starting, I would suggest GameMaker (http://www.yoyogames.com/gamemaker/windows#requirements). That’s what I started with when I was about your age, it thought me a lot. You can start with simple drag & drop game logic and later you can use a programming language. I then later went on to study game development, and everything I learned from GameMaker helped me a lot with my programming course!
Hope this helps 
One more really great thing about Unity is the support community behind it, with such places as Unity Answers and dozens of forums an wikis to help you along the way.