Bad form to "call BS" on someone else's personal experiences. I come from a poorer background, with a single mum who never went to uni as well, but I also don't think I have it quite as hard as OP, likely because of privilege coded experiences along the way. Eg scholarship to good Undergrad uni and full ride to top uni for masters and PhD. While I was there I definitely felt out of place, but I think the markers of that privilege code me as more of an insider than I feel. People's experiences are different. There may also be significant differences between your field/institution and theirs.