No one understands Angela Mitchell; not her neighbors, not her co-workers, not even her slightly twisted younger brother.
First, when you start mentioning younger brothers, I think this is a YA novel. I'm not sure why, but younger brothers are a fixture of YA. Since the younger brother never makes an appearance in the query again, I suggest you change this to family, even if her younger brother is her only family.
I also don't get the segue from people don't understand her to murder.
My education degree is from the University of Iowa, though I've spent most of my career in newspaper advertising.
Thank you for your time and consideration.
This query isn't quite a mess but I'd read the pages just cause you have the one thing I look for more than anything: voice. I'll bitch from now till the cats start waltzing around the kitchen with the cows who've come home about punctuation grammar and diction, but I can fix all that, and I WILL, if you've got a great voice.