Living as the eldest daugther in Korea

In 1993, my mother had her very first childbirth. It was a daughter. It was me.
I became the eldest daughter in the family. Then I came to have a little brother right after 17 months. Yeah, it just happened.

The label as the eldest daughter has been the premise for me to have a so-called special connection with my mother. She used to share pieces of her mind with me (maybe it's more appropriate to call as chunks, not pieces), and I listened to her. I ate them and tried my best to digest them.
She hardly hesitated to filter out which concerns bothered and confused her.
I was knowing pretty many parts of family events, such as how her husband's business was going on, how her mother in law stressed her, what kinds of new private education my brother needed, etc. Honestly I was unconsciously proud that I was the one who could got her every single emotional update. The thing is, the more she shared with me, the more I pitied her. The more I pitied her, the more I desired to react to her. My default mode of attitude towards her was 'pitying', and this seemded to patternise as perpetual conversation. Feeling bad for her, I was prone to say "Sorry mom", instead of "Thank you mom". I don't know..I couldn't simply thank her, because just thanking was not enough to compensate for her struggles.

I was also implicitly supposed to be a good assistant to her for domestic labours.
Umm, it was when I was 14 yrs old, and my little brother was 13. My parents were working during the daytime, so simple cooking and washing dishes were all of our shares. One day she left an empty large bowl in the sink before she went out for work. She asked me to wash it while she's not at home. I went to the sink for washing (it was like 14-15ish pm). But then I found there were many more dishes to be cleaned since we had meals after school. I suddenly found me doing this alone so unfair, despite I was accustomed to it. Although I could have just done it as I used to do, I asked my brother to wash them (for the first time). He said he couldn't. I asked him why he couldn't. Then again he said he just couldn't, because he had never tried. My brain went into a cold because I was honestly shocked that could be a reason that he couldn't. Eventually, I washed all dishes except for the big bowl. Perhaps it was like my last self-respect, leaving at least one thing undone. When my mom came back home she asked me why I didn't wash the bowl. I sincerely asked her :'why does it have to be me who's washing dishes and pushing a button of a laundry machine?' She was speechless. She silently wore rubber gloves to complete the job.

Yes, now I'm telling you that I've been stressed out from jobs that I was implicitly granted. And yes for some people it may sound like whining or self-victimising. I don't deny that I'm somehow whining. But still, adding a bit of generalisation, it's almost like one of the nature principle that a firstborn daughter is likely to have tricky chemistry with her mother. I guess for her I am an enourmous part of her ego.
I bet she didn't really intend to let me be a communicator and domestic choerer.
Likewise, the fact that I'm the eldest girl has classically been a sufficient reason for my parents to reflect on themselves. It was not long ago that I realised those missions have been sitting quite heavy on my stomach. I'm aware that my stomach has been hugely filled with her pure love about me, but maybe some sub-love (some parts of her love) has been sadly a burden to me.

Therefore I'm curious if something like a declaration for myself could emancipate all of the stress that I've implicitly had as the eldest girl.
Here is the declaration.

"Hereby I admit that I've been overly immersed in my mom's emotions.
Hereby I admit that I can sometimes look indifferent and cold when I'm not empathic.
Hereby I admit that my room can look unorganised sometimes for whatever reason.
Hereby I admit that I can be quite clumsy at cooking and ___.
Hereby I declare that I'll try not to feel shame on these.

I won't feel bad for myself even if I can't read her minds.

Ah wait, I think I dismissed one thing to mention.
Hereby I admit that this declaration can lose its validity anytime when I can't free myself.
Meaning, I admit that it won't be perfectly done at the moment.

This line is sort of like a in shield in case I won't make the declaration. It will protect me from feeling miserable when I go into the same stress as the eldest girl again. Meaning I'm already predicting that it's very likely that I'll come back to the same points of pressure and concern. This can collapse later on as many sorts of declarations have been in histories.