I think her “I grew up poor” complex must come from the fact that she went to a private school (paid for by her brother). So she probably only saw people who had a lot more than her. What she doesn’t realise is that, had she gone to the local comp, she would actually recognise just how privileged she was. There are so many kids whose only hot meal is their school dinner. But I guess all she saw were the kids who were constantly going out to fancy restaurants and always had the latest gadgets or whatever.