is it right choise ? Guide me

Database anything is a good job choice, IMHO. I can attest after finishing Pragmatic Works Foundation program that BI is very cool technology and can be fun if you are interested in it. There is a ton of jobs out their for BI positions, with in the US.

If you want to stay employeed as a DBA it is always good to be, I would at least become familar with all aspects of SQL Server. The BI stack with SQL Server is pretty big and can take some time to learn all of it. I would probably focus on SSIS and SSRS since those are most often found in shops.

Personally I would only recommend taking a look at all the technologies close to the main DBA part of SQL Server, so SSRS, SSIS, SSAS, etc etc etc and then pick what interests you the most. If you dont enjoy what you are doing then there is no point making it your career. I agree with the answer that says you should know about all aspects of SQL Server but aim to specialise in something you enjoy.

I'm sure learning BI fundamentals and any well spread BI technology is an excellent career move. I'm pretty sure Microsofts solutions will stay and gain market shares. But if they don't, you'll still benefit from having learned BI fundamentals and having learned a BI suite.