Yes you should. You learn grammar only using it and paying attention to it and if you got it even half correct it's enough if your plot is killing it.

Goooo

And i can help with the grammar if you like /o\

Go for it! You never know what could happen. Maybe people will like your writing more than you think. It happened to me. I honestly didn't want to at first, but I was like yolo.

sure, that way you can get feedback and improve