above gluteal line

When I was a nursing student and gave my first IM injection I obviously was nervous and shaking. I went ahead and gave the injection and whao behold I ended up giving it about half an inch above the gluteal line and the patient mentioned it did not sting at all. When I came back the next week the word spread and several patients (A LTCF) asked me to give their injections. I am now a licensed RN and gave my first IM injection under my license with shaking and I ended up giving it half an inch above the line (it was literally a fifty fifty chance). My patient ended up talking to my preceptor and said the following "I like it when you give injections but Matt's was a lot less painful as he gives it above where you do." All my subsequent injections were acceptable (I ensured I had someone observe them) with aspiration and all necessary procedures with the acceptable placement. I talked to a psychiatrist and he saw no concern about this. Can someone please help correct me if this is ok or not? For the time being (I gave about 100 injections since then) I no longer shake and give occurring to set protocol).