I understand. I've had similar problems "saying no" when people ask me to do stuff, at the sacrifice of my own time & sanity. If there's anything I learned when losing my weight before, it was that it's OK to say no. No to 2nds no to people who want to take up your work-out time, No to family, No to friends... I expected the world to come crashing down because I took a stand, but really - it didn't. People were a little taken aback initially, but then they said, "Oh... Ok." And it was all cool after that... and I finally had some time for ME!
As for kicking yourself about not finishing school earlier - don't. You're doing it now, right? I kicked myself for not completing it earlier, but I'm 30 and have been in school continuously since I was 3 years old. I look at my 27 yr old boyfriend and wonder why he could be done with everything (including grad school) by the time he was 22, and the answer is... he lives his life, and I live mine. We've had different circumstances, different attitudes about school, different goals and objectives in life, etc. You can't be someone else - you can only live your own life, which includes choices about what to do (if anything) about "to-do" lists thrust into your hands.
To-do or not to-do; that is the question - I know all about going home and wondering "Who are these people and how the heck am I related to them?" but they are your family, and are obligated to love you whether you do the housework for them or not. I refuse to pick up my family's messes (clutter or otherwise) and it's been empowering to do so, not to mention has eased my mind considerably to learn to accept the fact that it's not something I can (or need to) control.
My brother and sister seem to resent the "abandonment" somewhat, since I'm the oldest, and oh btw - I "abandoned" them when I left for college too. But you know what? I had to grow up - it's time for them to do so too. My parents and grandparents, on the other hand, are proud of me and glad that I've finally learned to make my own (good) choices, take control of my life, my education, my work, and my weight, and tell me they no longer "worry" about me "making it on my own".
So, I guess what the common theme here is, "Live your own life, and feel free to say no" in words or actions. If a to-do list is shoved in your hands, place it on the end-table or refrigerator (for the household to see/do) and leave it there. They'll get the hint. Don't be their scapegoat. Stand up to them, and a lot of the belittling comments, chores, etc. will disappear, because they'll finally start to respect you, even if they don't like the fact that they'll have to start doing the housework without you.
--Janis