Can I apply for patent before launching of website and how much time will it take to be granted a patent for the system?

You can apply for a patent before launching your website and many people do so they can be first to the patent office and keep their international rights open. You may put important rights at risk if you launch the website before filing your patent application. A patent application is how you will likely protect the system. It usually takes about 3 - 7 years to get a patent allowed after you file it. You do not wait for the allowance before you launch your website, though. Once the application is filed, you can launch the website.