i realy want to buy Unreal, but i dont know how to use c++, i have some games project that i wrote, so, do i realy need to know c++ ?
one more thing, my game project will have some conditions, like: when you fall from 2 meters with 50kg on your backpack you will break(or broke, i forget how to use it), i will have to write these conditions on c++?
obs: i dont know what is c++, i’m talking about that because some people said that i will need c++ to make a game
C++ is a programming language. UE4 has Blueprints(visual programming system) together with C++ so yeah, you can make your game with Blueprints only.
If you need more information head to the forums, documentation and Unreal Engine Youtube channel.
You absolutely do not need to know C++, especially as just a beginner.
You will need to know how programming works though. You can’t really design gameplay logic without understanding basic concepts like variables and flow control.
The specific backpack mechanic you describe would totally be doable in Blueprint though. Some of the included examples like Swing Ninja do far more complex things than that without using any C++.
so, where can i learn about it
But the question for me: i understand c++ and i can use it but is there a chance a create big games only with blueprints? (Big Shooter like Crysis or a MMO like WoW) I dont want it but … only a question 
Certainly not an MMO. Crysis however is, in a way, only “big” because it has high fidelity content; Its core mechanics are generally pretty simple. I’m making a procedurally generated first person shooter myself and I’ve only used Blueprint for it.
That’s a pretty big question for a pretty big topic! http://www.codecademy.com/ might be a good place to start.