If i do not register for gst then my tin will cancel?

No. Although nothing can be said for sure but you will be served a notice. The GST registration campaign is being run to ease bottle-necks.

It seems very hard that Govt. will be able to being in GST from 1st April so there will be more time given to register yourself..

But its a very simple process and given the opportunity, you should quickly get done with the process.