Should I give up on my sister?

Im always the one iniating and she never or sometimes respond but she never and she gans up on me with my brother with him she talks but with me she barely talks and acts as if im the crazy one if i call her out on it. Im very dissappoint in her because she is supposed to be a sister like i was too her all those years, i always supported her and when she wants to hang out i always make time for her... Im so tired of her behavior and i feel like she is healous or sonething she isn't very warm and social and i already put an end before this but she came begging after 6 months and later on she ignored me again... what should i do? Im 24 she is 21
Should I give up on my sister?
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