At the Bottom of the Stairway to Adulthood

At the Bottom of the Stairway to Adulthood summary:

Natsu has never had a good relationship with her older sister, Aki, or her friends she always brings home. One day Aki brings home a girl that is quite a bit different than all the others and Natsu immediately likes her. When she overhears Aki and her friends talking about the new girl behind her back Natsu thinks, "If only she was my friend instead..."