i feel i can't study for long being of age 21 feels so late for lazy like me to get on the track again and crack sbi as it need years for average to start from scratch and crack with giving 8-9 hr a day study i feel it's impossible for me&i am late to do something and now even my cousins boycott me

Ayush, I have a plan for you. If you are willing to take it up, it will help you design your life in an amazing way. Please read through it and check if you can work on it. Would like to listen from you about it. There is something called a Marshmellow test. It is not a clinical test but a simple test that can help you start from the scratch.

If you are not able to study for 8-9 hours at a stretch, it is ok. Because you are no more a kid and you are already 20 years and the brain evolves from that of a kid to an adult. Now for the entire first week, study just one hour a day. Just one hour. That one hour concentrate on English grammar. You have the books that we mentioned in our previous answers. But again for you:

• Word Power Made Easy (by Norman Lewis)
  This is the go-to book to improve your vocabulary. It is not a book to be read but a book to work with daily to enrich your vocabulary.
• 
  High School Grammar and Composition( by Wren and Martin)
  It is a very good book for people who want to improve their grammar skills. It helps to understand and conceptualise different aspects of grammar and it is a must have book for anyone with poor grasp on verbal ability or who wants to make up with the basics of english.

Only read for one hour an entire week. And without breaks, An adult 20 year old brain can focus for an hour atleast without distractions. If you concentrate and study non stop for one hour for a week, do reward yourself with by playing  a video game of or whatever you like. But remember this is after 7 days of 1 hour practise in English. Remember that you are trying to build your life and if you genuinely want to succeed, there can be no cheating in the preparation or tis one hour routine. All you need to do is practise for 1 hour and the rest 23 hours are yours to do whatever pleases you. Slowly we can increase the time from 1 hour to 2 hours and so on by stretching the limits of your brain. If you want to genuinely succeed, this is one technique that can help you. The rest, we leave it to you.