Not an expert, but this question has been answered before. Lots of good information in these following threads, including answering very similar questions about this same topic.

https://www.reddit.com/r/AskHistorians/comments/3vo2xj/did_christopher_columbus_really_think_he_landed/

https://www.reddit.com/r/AskHistorians/comments/2p3qhu/why_did_the_misnomer_indian_stay_in_place_for/

https://www.reddit.com/r/AskHistorians/comments/438ucy/george_carlin_and_indians/

Hope this is helpful.