First of all, there is no fixed or right time for anyone to do an MBA. It depends on person to person. There might be someone who has a reason to pursue an MBA at the fresher level or there might be someone who finds his/ her reason to do it at a later stage in life. And yes this is true for Indian B-Schools too where a person with work experience is also adding to the diversity factor, if not in terms of gender or academic diversity.
Now, coming to the question of whether doing an MBA from an Indian B-School after 3–4 years of work experience. My take is Why not? If you think an MBA can add value to your profile and your decision-making skills then age is just a number.
Talking from personal experience, I’ve worked for almost 4 years in different sectors of Consulting and in Banking domain and then took a decision to go for my MBA and till now I think that’s the best decision I’ve ever taken. Entered the gates of my dream with little nervousness about the thought that I might be one of the oldest people in my batch but to my surprise, I was wrong a long way. Just to add an example, we have a mother of 2 studying with us in the same classroom and her passion is unmatched. There are many other people with around 5–7 years of work experience also in our batch.
Now, some have the notion that more experienced candidates are not preferred by companies during campus placements. To some extent, I would say the answer is Yes. But, if you're in India's top 10 B-Schools then going for your dream is definitely worth it. After all, being in the top B-School, one has already proven that he/she is amongst the best minds of the country and all the companies value that. The brand always matters. If you've got a good brand on your resume, then no company will reject you or at least there will be someone to accept you in the worst-case scenario which generally doesn't happen.
According to me, the question itself is not correct. Instead of asking whether one shall go for an MBA after 3-4 years of experience, one shall ask why he/ she wants to do an MBA after so many years of experience. All have their own unique reasons. There will never be 2 persons having the same reason. Generally, people with many years of experience either want to switch to different industries and roles that they are working currently or they want to go up the ladder within the same industry and explore the functional side of it rather than the technical front.
So, its all about when you find that one reason to do an MBA and Indian B-Schools admission process is changing big-way in terms of diversity. One needs to understand that B-Schools are not just only for placements, There's a lot more it.