As for your English grade… Good English doesn’t always guarantee a good writing. Do you like reading? There’s this 1 Chinese author that’s really amazing. She has won so many awards and I had to analyze one of her novels when I studied English in England. The novel was told from a point of view of a Chinese girl whose English is not very good. The whole story was told in a broken English!
Good luck and most importantly, have fun with your writing, my dear! :)