Welcome to Fan Fiction & Writing forum! First fan fictions aren't always the greatest, since many new writers don't have much experience. But I'm glad to try and help you out any way I can. Without further delay lets get started!
Going into your first paragraph I already found some problems. It isn't smooth to me. Your story is in present tense, I would re-write it to include some narration from now on. It could continue on in 1st person, but the character would have to be recounting the story from the future.
I opened my eyes. My vision adjusted to the darkness. Where am I? My ankles were submerged in cold water like I was in a shallow pond. But I felt like I was inside. It was too dark to see anything except for the moon that shone brightly above me. But how can I see the moon if I am inside? Nothing makes sense. I don’t remember where I was or what I was doing before I got here. In fact, all I remember is that my name is Brent Irving and that I am a Pokémon trainer. Where are my Pokémon? I check my pockets and they are gone. I began to panic.
“Boomer! Dash! Where are you guys?” I scream
Rewritten Example 3rd person. You the Author are Narrating the story. Which means your telling the story and everything happening to the character is present tense.
The young boy opened his eyes and had found himself laying on the cold dark floor. His ankles were submerged in shallow pound. He sits up and can't tell were he is at, it was pitch dark with the only light coming from the bright moon in the sky. Nothing makes sense to him, he can't recollect his memories. The only thing he can conjugate is that he is a Pokemon trainer named Brent Irving. He places his hands inside his pockets and finds them empty.
“Were are my pokeballs?” He says, panicking. “Boomer!? Dash?! Where are you guys?” He yelled into the air.
Rewritten Example with 1st person; The character is the Narrator. Which means the character is retelling the story and everything is past tense.
I opened my eyes in the darkness, the only thing visible was the bright moon in the sky. I laid on the cold dark floor with my ankles submerged in a shallow pond. Nothing made sense in that moment, I didn't know were I was or what I was doing there. The only thing I remembered was my name, Brent Irving. As a Pokemon trainer the first thing I did was check my pockets for my pokeballs. They were missing! I began to panic as I yelled out for my Pokemon.
I yelled out into the darkness.“Boomer!? Dash!? Where are you guys!?”
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So pick which ever style you want You should continue writing it in first person as you are. I found that you keep switching back and forth between present and past tense, which makes it sound weird and not smooth. Your character is narrating the story, but everything is happening to him at a present tense. If you want him to be Narrating then it has to be past tense.To be blunt you really have to pick a form of writing in which to tell your story. It is confusing and it really stops the reader from having a good time reading your story.
You are breaking some of the basic English rules in storytelling. You have a good story going on. The only thing ruining it is how you write it. It takes work and some research to become a good writer. You have to learn the basics of how to tell and write a Narrative. Alright so I could go on and on. But I am just going to refer to this website right here. Read about what your writing and compare it to your current writing style. Also check out the writing lounge and ask some questions there. There are people here in FF&W that are more experienced than me and will be glad to answer any other questions you have. Anyways good luck and hope I helped you out. I'll keep checking back on your story later. This happens in most parts of your story.
Check out this link for detailed information! It will help a lot trust me! Once you got all of this down I'll check back on part III. Good luck Mate!