The best place to start your trip in India would be from the hear of India - Delhi. Delhi is one of the oldest sites in India that still holds to the vast heritage and culture. Also since people all over India move to Delhi, and have settled in Delhi from various regions within India, since it is the capital of the country you get to see and feel the diversity in cultures when it comes to food, festival celebrations and many more things, which I feel you will not be able to see in any other city.
Have a safe trip!
Have a safe trip!