I have 11 years experience on .net, should i learn data science?

Let me try and break it down slightly and expand on what @Dawny33 has mentioned.

Should you learn DS?

If ambiguous and open ended problem statements excite you, you should. If you love and continue to apply mathematical concepts beyond your college degree, you should. If you always question why before what and how, you should. Given your question however, I am tempted to say No, but it is solely up to you. What would you like and more importantly why would you like it?

Will your experience count for DS opportunity?

No. Can you build solutions that can be data products and feed some reporting and analytics using .Net? Yes. Being a DS myself, I work with folks who do exactly that. Are they part of my Job Family? No.

In spite of its similarities in some areas, Data Science (and analysis) in general requires a different skill set than a pure developer. It among other things can also require lot of data exploration, wrangling, plotting and research on a day to day basis.

Unless you are really ready to change your job profile at your career stage, and bear the ever changing and dynamic nature of DS, stay put and invest time in technologies that have synergies with your existing skill set.

+1 for Angular as I know how heavily my employer is investing in it.