My mother was born in 1929, old school and agoraphobic. I doubt she got the memo on either left handedness or red hair. Also, given the racial context, I'm sure she saw red hair as a "white thing." I once dyed my hair red and she lost it. I was 42.
I added my mother's narrative to add context to the story. You know, as if being a white looking mixed race kid in a Black home in a white town wasn't enough, LOL.
I'm glad your mom had the good sense not to allow teachers to force you to write with whatever hand.
PS, I wasn't a red head, but I still wasn't allowed to wear red. I was "too pale." Pink was also mostly out.