As a Class 11th student one is not eligible to join RAW .

Research & Analysis Wings does not recruit aspirants through direct recruitment process for agent posts.

Research & Analysis Wings is an independent body, it has the power to recruits aspirants as they wish, sometime R & AW recruits there agents and officers from Army, IPS, IAS, IB, CBI, or sometimes directly from Universities in very unique cases.

The entire tenure of a RAW agent is of nearly 2-5 years, after that they are allowed to go back to there old service of weather an IAS or IPS service etc.

If one want to join RAW directly then there are two ways.
1) RAW recruit directly through SSC holds, the a exam called Deputy Field officers Under cabinet secretary, there one can appear.

Cabinet secretary is an IAS officer, as cabinet secretary is the highest post of IAS, he is the one who handles PM's office.

2) Aspirants who TOP IAS exams are invited by RAS to join them.

This contains various case studies of reputed National and International Security organisations etc.

Then comes the training of one or two years, which is very usual.