Need help:transgender teen

I am a 19-year-old teenager from the city. I have been physically handicapped since the age of 13 due to a spinal tumor. I use a wheelchair all the time, and my body is paralyzed, so I am entirely dependent on my parents for everything. The issue is that I am currently a boy, but I have never felt comfortable in my body. I feel more at ease identifying as a girl. I have a lot of feminine mannerisms and want to transition to being a girl. However, my parents are against it. I once slightly shared my feelings with my mom about identifying as a girl, but she slapped me multiple times and said, “You’re already handicapped and a burden. You can’t do anything, and now you want to become a ‘khusra’ (a derogatory term for a transgender person). It’s better if we send you to a mental asylum.” I am now very scared to tell anyone, but the feelings are incredibly strong. I know in my heart that I am a girl, and I cannot continue living as a boy. I deeply want to wear feminine clothes and express myself as a girl. Please help me understand what I can do, considering that I am 90% disabled.