Why is my brother my mother's favorite?

My brother is 5 years younger and my mom treats him like hes ******* god. I am a straight A student and have managed to have have the highest average in my grade for three consecutive quarters, but all my mom ever does is say good. But if my brother gets a 100 on one ******* test she act like its the best thing that ever happened. My brother got a pet snake and it died and the next day my mom bought another one, even though they both cost $100, but if I want a ******* kitten I cant get one even though its half the ******* price of a snake. I get invited to the IBM E-Week and my mom act like its nothing, but when my brother says that he wants to learn how to swim and she is practically rejoicing. In second grade my average was 100 for the entire school year, and what do I get, a pat on the back, that same year my brother got his first haircut and my mom goes around bragging about my brother's hair. When I was 8, I sprained my ankle, the day after I got the cast I woke up but I could not move because it hurt so much and my mom did not even TRY to help me get out of bed, but my brother falls and gets a cut and she acts like it is World War 3. One day I was riding my bike down a steep incline and the brakes gave out so I crashed into a barbed wire fence and simultaneously had an asthma attack and she babies me for 2 days then its back to normal . I love my mom and all but even if I were to try and tell her how I felt she would say that it isn't true.