Spoiled Little Brats

I grew up in the lower class. My clothes we're either hand me Downs or clothes from the clearance rack in Walmart. I've been living with my friend and his 16 year old nice. She irritates me to no end. She's had everything handed to her. She's driving around in a brand new Ford focus and complaining about it. Her mother sends her hundreds of dollars every month and she complains cause it's not enough. Am I wrong for being irritated or is it because I have to work for everything I have and she doesn't.