Yes you can start now as well. Stay positive and don't think about such negative thoughts. It's better to be late than to be never. So don't think too much and keep studying and focus on quality and not quantity. It doesn't matter if you are giving 5 hours or 10 hours or 15 hours for studies, the main aim should be clear maximum concepts and have a better understanding of all the topics. Your hardwork will be worth one day so keep focusing on the process more than the final day and if you master in this process, then surely you will achieve your goal.

Refer to the site below for more detailed information..

https://competition.careers360.com/articles/sbi-clerk

https://competition.careers360.com/exams/sbi-po

Best wishes. Thank you.