For coding, there's a great organization called, "Girls Who Code" https://girlswhocode.com/ It's a great place to get started and have support from others in your shoes as well as experts who want to teach. This is also a great work field for girls! A lot of girls are actually great coders and really like it, so take a look.
I'm not sure for writing/composing music. The first step might be to either learn how to play music or sing by ways of reading sheet music. This would get you used to seeing how notes display on a page and what kinds of notes tend to get paired together. Knowing how to play the guitar and piano are great because then you'd be able to let your mind wander while your fingers play and songs might write themselves. Knowing how to read sheet music would then help you transpose the notes onto a page and viola! You're a song writer.