Hello ECwakerr33: I see this is your first post here on PC. So... welcome to PsychCentral... from the Skeezyks! May you find the time you spend here to be of benefit.

Many years ago, when I was in college, I had a psych professor who said that mental illnesses are simply extreme examples of the same behaviors we all exhibit every day. For example, we all wash our hands periodically throughout the day, depending on what we're doing. But if someone starts washing their hands over-&-over so often that their hands become red & raw & they just can't stop washing... then it rises to the level of Obsessive-Compulsive Disorder. Does that make sense?

So anyway, I don't know whether or not the behaviors your sister exhibits could be considered to constitute a mental illness. This is really something for a mental health professional to determine. As far as the birthday party incident goes, it sounds to me as though your sister was just excited & didn't think about what she was doing. I'm sure every person on the planet has done that a time or two. Perhaps the things you're observing are just youth... I wish you well...