I never thought i would say this but i hate my sister!?

Sorry to say it will never get better or improve on any level with age. My sister is self envolved as well. She only calls or fb me when she needs something or has something to talk about that she needs advice on. I am the younger sister yet I seem to always be the one that helps her out. we are in our 30s now and its still the same to this day. Just know you cant change her or how she is but you can change you and not be a doormat for her anymore. Let her know how you feel and stand firmly. She cant be mad at you forever and will eventually realize that she needs you.