Why am I so mean to my parents?

So, I'll try to make this as short as possible.
I've always been so introverted and shy, but up until 12 yo, I had an awesome relationship with my parents.
Ever since then, everything they do annoys me. I am always so mean to them, even when they ask me the simplest questions, when they wanna know how my day went, which college I want to go in, whenever they show interest in my life- I instantly back off and start being mean for no reason.
I'm not like this with my relatives, I am so open with them and love talking to them, and I feel so bad for my parents because I am never like that with them.
I mean I love them to death, but I just can't explain it, they've never did me anything wrong yet I am still acting this way, whenever they want to talk to me I get so annoyed.
What is wrong with me?
Why am I so mean to my parents?
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