TLDR: use 0-based indexes now and in the future (and in the past if you can)
I get so annoyed when indexes aren't 0-based.
Indexes should be 0-based. A 1-based index confuses me (and many other people) because i'm used to 0-based indexes, and so are many people.
That's why i write 11th september 2025 as "2025-8-10"