Since she has arrived early before and you have let her in, she thinks this is normal and okay. Adults are just like children...you teach them how to treat you. You are allowing her to push you around and then you are feeling frustrated and angry. You need to tell her clearly that from now on you will not be answering the dooor before 8:00am on the dot as that is your opening time. Do not answer the door...do not answer her texts or phone calls...nothing before 8:00. She will get it pretty quickly.