A first chapter review
The punctuation is fine enough, you do pretty well with the changes between descriptors and dialogue. You don't seem to have em dashes down, but that's very minor. What does really bother me, and this may just be an inkitt thing, because I see it here frequently, is the use of single quotation marks, or apostrophes, instead of actual quotation marks for dialogue (which is a big no no).
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The dialogue does have me concerned. It feels more melodramatic than necessary, but there is a fine line with that in literature. That being said, it may be the result of this next point.
First person present tense can be a real pain to write in and it leads to a lot of "I" and "He/She" sentences. I dislike this way of writing, but that is personal preference. Past tense has a more casual sound to it and I feel it works better for fiction. (Don't rewrite your entire story into past tense because I mentioned this, just consider how your tense factors into your phrasing.)
There are some weird moments with passive action in regards to what people are doing. You give little details on what your characters are doing, but they aren't what I would consider to be the details that matter. Since this is a first person narrative, you should be paying attention and pointing out details that your first person is prone to noticing. *One thing that really bothers me is the constant "I tuck a strand of hair behind my ear." which appears on almost every other page of the first chapter. It's a passive habit and generally something girls don't notice that they do (it also tends to occur more when conversing with people they like). If you mention this sort of behavior at all, it should be minimal. The key things to include (according to me) are major motion (stand up, sit down, walk, run, etc.), interaction (hug, kiss, obvious eye contact, signaling, etc.), and emoting (obvious changes in voice tone or volume, tears, obvious posture elements, etc.). Too many little things and it will feel like your reader is seeing the narrative through a magnifying glass, too many big things and your characters are probably doing too much.
An example of somethig to look at when it comes to writing down the right details would be where Ian bumps his shoulder against Kara (which is really a subtle thing, but consider this). There is no indication that that would be possible if Kara was sitting (which I thought she was). Her physical motion and observation are positionally stagnant for long enough that I had to go back and double check to see what she was actually doing at that point (she was standing, but she was just taking things in for so long that I pictured her sitting).
One of the things I noticed in your descriptors is an odd choice in adjectives for many actions. Kyle's "dazzling smile," for example, isn't something most family members would use. I might describe a sibling's smile as wicked, mischevious, or even charming, but dazzling has a certain romantic connotation that gives me a bad vibe in this instance.
Few bits of poor phrasing. For example, "It also takes a certain kind of mad to attempt The Mourn, yet I have always seen it as the logical next step." What kind of "mad" is meant here? Is it madness or anger? Both are relevant and possible, but it is unclear.
"They are trusted to with the most delicate tasks and responsibilities." That "to with" is probably a slip up from revision, but that is when you have to be the most careful. Writers often make the worst mistakes when they are trying to avoid mistakes.
I'm not going to point out every error you have (I would charge for that), but that being said you didn't have many. While I don't think (especially due to my limited exposure to the story) that this is publishing ready, you have done a better job than most writers I see on this site. Very few obvious grammar errors, even pacing, small cast (at least so far), and you've managed to build up an event without outright spoiling it. Actually, I want to elaborate on that.
Foreshadowing is fine and dandy. A lot of writers like to use it as a way of creating tension and exacerbating conflict that already exists. Some writers, however, use too much foreshadowing (and this is where my mini-rant begins). Divergent is an example of this, and a good example of what to never do when you write a story. If you want to write a twist, don't give it away, don't even make it an option, make it a reasonable possibility that you don't state outright. Divergent was well written, for the most part, but was cheeky enough to say (several times as I recall) "wouldn't it be wild if they used this to mind control people and take over the country?" Which then proceeded to happen.
From what I see in your writing (thus far), you have a buildup to a greater challenge for your characters, essentially introducing the players, without spoiling the plot. I hope that is how you keep it. Don't get too excited by your story that you forget to tell most of it.
Sadly I don't have time to read more, but if you take nothing else from this review, take that subtle indication that if I had time for more leisure reading that I would have at least given the next few chapters of the story a shot.