You have to consider the majority of who your audience will be: people from countries where English is used often. Not everyone is bilingual (either in general or with Spanish) or they may not be fluent enough in Spanish to go through a story without google translating and grabbing their dictionary (personally, I've lost fluency over the years because no one I know is bilingual enough to have a full conversation with). If you're not completely fluent in English (or you just have a poor grasp of grammar), then you may want to ask for someone to help beta read and edit.

I didn't understand almost anything, but If u asked about publicing your fic in spanish, I say - Yeah, do that! Maybe someday there will be more story in our national languages, because everybody prefer to read/write in their own language, doesn't they? :3 So feel free to write as you like to ^^

me gusta gatos y papas

me no halbo espanol

pero me tomó dos años de clases

Yeah um

1.1 years actually so
Sry