Why does my cat like my mom more than me?

I got a cat for my birthday 3 years ago. The first night in my home she slept with me. I feed her, play with her, give her affection, always clean up her vomit etc. and she doesn't like me that much?? She growls whenever I try to pick her up and shes scratches me when I pet her. My mom barely pays attention to her but she'll let my mom pet her and hold her and she won't growl. Whenever my mom goes downstairs and closes the door behind her she starts meowing and scratching at the door to get to my mom and growls at me when I go near her? Why is she like this? the point of my birthday gift was to get an affectionate loving cat, which she is, but not to me.. yet I give her the most affection.. Should I just stop paying attention to her and maybe get a new cat?