Hi anon! If you want to write, go for it! This fandom is very welcoming and helpful with new writers and I promise you won’t regret it!
I’m not fluent in English and when I started writing, my English was really really bad! But writing helped me to improve a lot.
My first beta reader was someone who just liked my fic and genuinely wanted to help with my English and I’ll be eternally grateful to her for that. The better beta readers must be your friends, though. They understand how you think and what you want to say, and they’re not afraid to be too harsh on you, which is necessary in my opinion, but can be painful if you don’t have a bond with this person. You have to trust them and allow them to tear your work apart for your own good.
So my advice is go for it, write, post your fanfics, only good things can happen to you once you’ve done it! Good luck! đ