Like your other question - this depends on what you want to do.
A lot of AAA games now use engines (usually million dollar ones) because writing a high performance modern engine is a huge multi year large team job. It usually means you can get your game or prototype up and running much quicker. Many beginners never ship anything becuase of this curve.
If you want to learn about how to do the nitty gritty details or you think you have a requirement the engine can't deal with then write your own.
Though if you have the source for the engine, starting with the engine and modifying it for your requirements is also an option.
Thx For You Great Answer Man.
I Decide To Learn Native C++, And Build My Game Using A Game Engine.
Thx For Your Help