i have completed AME training. i really wanted to design aircraft .?

It is your choice, you can start from the sketching manually for your idea then study it; the effect whether your consideration for your design & idea is good enough. It doesn't mean that if you're not graduated as an aeronautic engineering then you're not allowed to design; there is no such rules for designing whatever you wanted. you can do whatever you want to do. CAD is just easy to study, if you know how to draw you can learn it easily.

I suggest you begin with whatever job you can get at a business that designs and builds aircraft, and start the process of working your way up. As you are probably aware, even aeronautlical design engineers concentrate on just ONE part of any aircraft design.