Why does my sister push me away when I try to help her?

That's a tough question to answer but in my experience it's because of either 2 things. 1 which is that they want help but they don't want to accept the fact that they are in need. 2 which is that they struggle to know that you are there to help them and that you actually care. It can also be because she isn't ready to deal with it. she probably understands that you are there for her and that you will help her if she ever needs help. I would guess that she isn't ready to accept help. Just you being there might be the help she needs, Just stay close to her and remind her that you are always there for her.

Is there a big age difference between you and your sister? Are you the only siblings or are there more. I have 3 sisters, two that are older and one younger than me. Have you been able to talk to your sister about your feelings to see why she pushes you away or is that not something you have done yet. Are these topics that you feel you can help her with or are you just trying to be a supportive sister, does she have someone else she can talk to about her problems like a friend or partner?

It is a noble and kind thing to want to help another person, but not everyone wants help. Have you asked your sister if she wants your help? This conversation would be a good starting place because not everyone has the same reasons for pushing people away. Maybe your sister does not know that she is pushing you away or is pushing you away for a reason that is different than her not wanting your help. Help begins with listening to the other person and asking questions. After this talk you both can decide how you can help the way your sister needs to be helped, or to not help at all.

she may be doing this purely because she doesn't know how to accept the help or maybe doesn't feel deserving/ in need of the help you are trying to offer. she may also be doing this because she doesn't feel you can help her or that your methods of help may not work. sometimes people can't see that they are in need of help or that they aren't doing what's right for themselves. just as well as the fact that some people feel undeserving of help, that they caused the problems they are going through weather that is the case or not and that if they caused it then they should be able to get out of it themselves.