I have read about offline wallet but i am not comfortable for doing that, its too scary for me.
I would probably go for a direct bank withdrawal.
Print out a paper wallet and keep it in your wallet. You should feel a bit more comfortable about that. Just don't store massive amounts on your online wallet.
yeah never stored big amount in wallet online , people will try to guessing hacking etc to get claim your adress
That's not the problem. Anyone can do that with sufficient malware installed on the victims computer. The biggest and the most troubling problem is the reliability of the company that's keeping your private keys. They could pack up and go whenever they want to.