Hey Abhishek,

You cannot join DRDO while you are during your BSc but you can sure do go for it after your graduation i.e. after finishing you degree. Though if you want to go for the post  store assistant or an administrator assistant you eligible for it, In fact its eligibility is only 12th pass.

In a simple language what I am saying here is that most of the technical positions/Higher level positions are beyond limits for the people who are not a graduate. In DRDO there are clerks who are just 12th pass, on the other hand there are officers who are graduates. That's the difference.

You will get more opportunities after you graduate.

Hope it Helps!

Good Luck