Hello there. I'm a person who enjoys writing fanfics. My current project is in the first person view, like yours. You don't always have the problem, but it is evident here and there in your chapters. You use "I" too much. An example from the first chapter is this:
"I had some money which I had received on my last birthday, when I turned 13."
There are three I's in that one sentence. I know it's difficult to avoid using "I" but it's generally recommended to not use "I" too much. To avoid using it too much, you can reword the sentence. It'll make it more interesting and less repetitive. Here's the same sentence that I reworded:
"I had some money which had been given to me as a present on my 13th birthday."
Avoiding the overuse of me's and my's are hard too. :/
Anyway, when you're writing future chapters, reread the chapter. If you notice that "I" is being used too much, you can consider different ways to reword the sentence and your writing will improve alot!
Keep going with the story! To me, it's a bit more original than you may think.
~ Darkrai