Back in Finland some decades ago, there was pretty decent coverage of India in three topics: world religions and the history of religion; European explorers, colonialism, and imperialism; and "modern" history with Gandhi, Nehru, the partition, and the wars. There were also some passing mentions in other topics. Overall, we probably spent more time on Indian history than American history.
This is sort of trivially true, in that there is generally literally no point at which a person's cognitive abilities are "fully developed" (cognitive abilities being non-uniform in development, and some aspects of cognitive ability tending to continue developing until very late in life, long after most of the rest have been declining for quite a long time.)
The History of India is a multi-branched tree with the main branches being; a) Oral Tradition b) Linguistic Tradition c) Philosophical/Religious Tradition d) Literature/Poetry e) Mythologies f) Historical writings g) Writings by other cultures/civilizations h) Archeology. All of them have to be studied to get an idea of what India was/is.
1) A good book to start with is A.L.Basham's The Wonder That Was India: A Survey of the Culture of the Indian Sub-Continent Before the Coming of the Muslims.
The Book: https://archive.org/details/TheWonderThatWasIndiaByALBasham_...
The Author : https://en.wikipedia.org/wiki/Arthur_Llewellyn_Basham
2) For a modern idiosyncratic and funny take, see Sam Miller's book A Strange Kind of Paradise: India through Foreign Eyes.