Jenna, I sort of know where you're coming from. My sis was a good student. She didn't get outstanding grades - just good, and she went on into a career of sorts.
She always had a nice house, a good job and a good salary and was always held up to me as an example. My failure to do likewise was very much emphasised, I felt. I especially remember, when I told them I was pregnant (eight months after my wedding, btw), mum turned to sis and said "isn't she a sod?" This was because sis had chosen to stay childless and because I had been a 'troublesome' child (I cried a lot and was clumsy) to mum, who thus didn't think much to kids either (although she adores my boys).
Like you, Jenna, the tables have turned. Sis has been divorced twice, has a new fella and now has little time for mum, which mum resents. It's a bit of a pain when I'm the one who gets called out to her in the middle of night because she's fallen off the bed or whatever, and sometimes I still feel Mum won't take advice unless it's from sis, but I don't feel quite the pariah I used to.
Still difficult to live with, though.