Really good start!
(Ongoing, read until the end of chapter 5)
Read the story now
This is a really good start! You've set up the family dynamic very well, and I really liked that you made it different from all the other 'step-parent' relationship stories. It was refreshing to see that she had a good bond with her step-mother; it made me a little sad to think that if she and Gia got along too, then Kalani could've had a family like before her mother passed. It's unfortunate that they don't, but Gia doesn't seem like a nice person at all, so I don't blame Kalani for wanting nothing to do with her.
The characters are developing well; I liked the interactions between her and her father, and her step-mother. They were warm and loving, which contrasted greatly with the icy, tense encounters with her sister. The fact she's marrying Kalani's ex is a bit weird (does she know they dated?). He comes across as a dickhead - messing around with Kalani while his fiancée is in the same building! It's completely unacceptable behaviour, regardless of how Gia has acted in the past.
One thing I'd say is to make sure each bit of dialogue (from a different person) has its own line. (For example: "I went out last night," Bob said. (new line) "I didn't hear you leave," Jim replied. "Where did you go?" (new line for Bob's response) etc.) It helps with readability and makes it so that you don't need to clarify who's saying what all the time.
Anyhoo, good job with this. Keep writing (and welcome to Inkitt)! :)