Me and my sister shear a friend but at times i think she like my sister better?

I think it's normal for that to happen. It's hard to equally like each other in a group of 3. There will always be someone left out. Maybe she doesn't like your sister more. Maybe they have more in common (is there an age difference or anything...because that makes a HUGE difference) More info=more help ? I hope i helped. Good luck. Don't feel bad though because I'm an a group of 3 friendship. These things are normal. but in the end, we're all good friends still.