Air 19345At this time I have no college in my mind because it was long 3 years gone after my b.tech and now I am worried for the same

You will not be able to get a seat in good colleges. Since it has been 3 years the colleges, you must be having some work experience for the past three years. The colleges you are going to get will not do much good. Since there is not age limit for GATE it is better to consider taking the exam again and then going for mtech.