My mom isn't happy I'm pregnant

So I just gave my mom the best news of my life and she's is not happy at all she's pissed off and I don't understand I'm 21 I own my own home with my fiancé we've never asked my parents for help ever I don't understand why she responded so poorly she said I'm not ready and I'm too young and I'm not ready for that much responsibility it honestly made me so depressed that I feel bad and feels wrong knowing that I'm pregnant I've been crying none stop my fiancé said she'll come around but I just find it unfair because my brother that's older than me had two kids with different girls while still living with my parents yet I live in my own and I'm not ready?? Sorry I just needed to vent.. 😓😢😢