For the course of Bachelors in Computer Application, one needs to qualify 10+2 or atleast a Diploma in computer Application. So after ITI you can't do the course of BCA but you can go for course of Diploma in Computer science & Technology. This will also land you to a great job. After completion of the Diploma course you can even pursue the course of BTech in Computer Science & Engineering as well through lateral entry (you will be provided admission directly to the 2nd year of the BTech course). BTech in CSE have a better career perspective than BCA, so you can definitely try it out.

For more information regarding the BCA consider the link below:

https://www.careers360.com/courses/bca-bachelor-of-computer-applications

I hope this helps. Wish you a great eve!