Indian Govt. has made Internship compulsory before joining a company so you have to do it in your 7th/8th semester. If you are willing for an internship, the right time to do it starts when you've completed your 1st year else after completion of 2nd year (most suitable). If you go like doing internship after completion of 1st year, you can do 3-4 internships and that will be too much beneficial with almost every kind of experience.

Hope this helps!!!