Okay, so it's pretty obvious that your story needs to be worked on. A lot. I get that it's your first story, but some of the things that went wrong with this story shouldn't have. I could see your idea of what you want shine through, but sadly, it didn't develop into something more. Here's some things you should take into consideration....
Read the story now
Cover - The cover of your story isn't really appealing to the eye. I could barely see the title or your name. I use the Desygner website to create the cover for my books and you can use it too if you want. There's also the infamous Canva app that you can download to make your cover stand out.
Summary - The summary of your story is what pulls a reader in. It intrigues you and makes you want to read your story. Your summary was a bit dull and is in need of reconstruction.
Characters - There was absolutely no character development whatsoever. I liked Rey at the beginning but then I didn't see her personality shine through except for the knowledge that she's a Little. Benji was also on a stand still and how they got together was way too fast. If this was a short story then fine, but you need to reconstruct her life before she meets Benji and when she does meet him, you need to work on their closeness before she ends up living with the man.
Plot - Having a nice plot is crucial to a story. There was no plot here. How Rey got fired from her job, ended up going to the interview for a big company and getting the job the same day, baffled me. It was like the story was at level 1 and jumped to level 10. The story kept falling through and there wasn't any stability there....
Grammar - As you said, there was a lot of grammatical errors in your story. The full stops, commas, and quotation marks were not where they are suppose to be. Even through your dialogue, I saw quotation marks on sentences and thought that someone was speaking when in fact, they weren't. It was very distracting and confused me throughout the story. I recommend downloading the GRAMMARLY app. I use it in my stories to fix the grammatical errors and you can use it too if you want.
I love the concept you have for your story which is the Dom/Little relationship that's going on here. This story just needs to be thought out properly and executed properly. I don't think you thought this story out but working hard on fixing those mistakes will no doubt make it a really good book.
Hope this helped you. Good luck!