J.T.
Good morning! This actually happened to me. I moved back from Hawaii and in with my parents until I could sell my condo in Hawaii. My daughter was a little over a year at the time and my brother and sister still lived at home. When I moved home the rules were like I was 18 all over again. I had a curfew of 2am. I also could not stay out all night unless I called in to tell them I would not be home. Even when I did that my mom asked a million questions. My daughter would go with me if I did stay out but my mom would frown upon it and made sure I knew she didn't approve of me staying over (usually at my new boyfriends house) with my daughter. Also, I was NEVER to assume that anyone in the house would watch Briana while I went to the store or tanning or any place I needed to go alone. I alwsys had to ask someone to babysit. I had to be careful how many times I asked too because at one point when I was job hunting I asked my mom too many times to babysit and she pointed it out to me that she felt like I was taking advantage of her. But overall, I had the same rules as my other siblings in the house. I had to clean up my room like everyone else and I had to make sure I picked up after me and my daughter out of courtesy. I had to understand that this was NOT my house, so I was to be respectful of everyone that lives there and not take over the house with baby/kid stuff. If Briana started to cry too much I had to take her for a car ride as to not bug everyone else. I had to respect my brother and sister's space and make sure Briana didn't roam into their rooms. That I think is the key with your younger daughter is that she may think her own personal space is going to be compromised by her older sister and her kids. If she wants to go into her room and turn up her radio, she should be allowed to and not have to worry about little ones roaming in and disrupting things. The younger sister is NOT a constant babysitter either and she should be asked if she could watch the kids while the older sister has to run an errand. Same goes for asking you to babysit. And you HAVE to say no once in awhile. Your life does not revolve around her and her kids schedule. She needs to be pushed to find other babysitters or change her own schedule to make it work.
I lasted about 9 months at my parents house before I finally sold my condo and got a house of our own in St. Charles. Thank god! I loved being close to my family since I had lived thousands of miles away for 6 years, but I was sooooo... ready to get a place of my own.
I have always been really active with Briana. Heck, I had Briana on the first day of spring break in graduate school and both her and I were back in class that next week. She started college early. LOL. We travel a lot and like to experience new things. With that being said, me and Briana were out of the house quite often doing things like going to the playground, friend's houses, fun places in the city, etc. Your older daughter should try to do the same thing. Get out of the house with the kids, go to the playground, go to the zoo. This will give space to people at home and some peace and quiet from time to time.
I hope all this has helped. It doesn't work for everyone but I hope your older daughter can understand where she now fits into this "new" home of hers without compromising everyone else's lifestyles. Good luck!