Is my sister offended from me cause she has 3 kids and I want the child-free life?

As sisters does this make a clash between us? She only talks to my mom and never ever calls me to talk about anything. When I'm very upset and feeling alone she won't pic up my calls or tell me anything that would help me. And even when she does give me advice its in a rude tone. I don't understand why she is like that, I mean I never did anything bad to her... We are 7 years apart, I'm 30 and she is 37..

One time she told me when I'm married to someone one day, she said she will not be the same with me and won't talk to me the way she used to...

Any idias why she is like this with me?
Is my sister offended from me cause she has 3 kids and I want the child-free life?
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