Am I being unreasonable? Parents want me to pay rent.

I'm 21 years old and I still live at home. I make really good money but only have a part time job so I'm saving up before I move out which should be within the next year or so. Basically I bought my own car brand new (paying for it myself), I buy all my own clothes, make up, gas, insurance, cell phone etc. My mom recently said I should pay $100 rent which isn't a lot I know. But I said I didn't think I should considering I already pay my own way so much. I know it's only $100 but I mean I'm an only child, we're not "poor" by any means and I know how to be responsible with my money. She's mad at me for saying this so I'd like to hear what you guys think?
Am I being unreasonable? Parents want me to pay rent.
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