Hey Jewlyn how are you? I thought the start was really good, when you were talking about the memories (Although I do feel like you slightly overdid it)
I agree with Helen, I didn't finish reading when I saw there were more and more letters. There's no tension or momentum to make me read on. When the story started, it reminded me of the Old Guard movie (it's on Netflix if you want to check it out). The movie starts with Andy walking— she's the leader of these four immortal warriors. Then Buka (one of the warriors) show us on a motorcycle they walk and talk for a minute, then the scene cuts. Next Buka is booking for a hotel, and Andy's just looking around. A group of girls behind Andy take a selfie, and Andy realises she's in it. You see Andy have a flicker of “shit!” then she goes up to the girls and offers to take the pic for them. She deletes the previous image of their phone then takes this pic. The viewer, “Ah, why doesn't she want her picture taken, who is she?” And we all immediately watch on with interesting.
I know a movie is plotted differently from a book, but the point, even though it wasn't action-packed beginning, there is a reason for a viewer to watch on.
The start of your story needs to have some sort of “conflict” something that happens that makes the reader want to read on. This is usually why show don't tell needs to be applied. Start the story with a scene, that introduces your protagonist. The scene can foreshadow what is to come, but show don't tell. You can show the memory confliction rather than tell it.
Helen is right, the letter system is tricky and there are honestly just too many letters. One letter? Fine. Two? Eh, you're pushing it but the letters were short but okay. Not the number that you did, it just killed it for me.
But I think the story has potential, I liked your style of writing, it was dark but fluid. I know intros are tricky, you'll get the right one sooner or later don't worry!
I'm currently editing the first draft of my novel, not sure where I'll be by mid-october, but just holla at me at the time and I'll see!