Earlier quoted context omitted.
For what it's worth, I think your mother's attitude is shared by the vast majority of Indian-Americans, and even first-generation Indian immigrants like me. In India, there are egregious things reminding you about it, i.e. literally every government form ever -- but in the US it's reasonably easy to ignore and forget about completely unless you go out initiating conversations about it, or are unlucky enough to run in…
As an American Indian I found the whole asking of race in government forms to be a bit crazy. I usually end up putting “N/A” or equivalent.
But this thread raises an interesting point.. asking about race or about caste on government forms could be potentially creating extra divisiveness, by making people identify themselves one way or the other and making them conscious of their differences.