I need some help with writing...

Hi guys. So as you know I've been working on my new story Flawed. I've been getting some critiques lately that I don't understand. Maybe you guys can help me?

-Some of your dialogue seems forced and unreal, and some of it comes off immature and childish. I knee they're tenth graders, but they would still have mature conversations. Also, sometimes the story doesn't flow well. It gets choppy and jumpy in some places.

-I know I should be giving you things you should improve on, and the only thing that would be is to make your dialogue sound more natural.

-I noticed a few things in this chapter. in the beginning of this chapter the speech doesn't feel natural, so maybe try making it sound like an accent or possibly adding little turns of phrases because it feels very…mechanic to me.

I figured since I got this same critique three times.. I need some help. I've never gotten this critique before so I don't really understand it.

If anyone would be willing to take a look at Flawed and give me some examples of "unnatural dialogue" or where it sounds forced, I would REALLY appreciate it. Those people didn't give me any examples, and I really want to fix it!

PLEASE HELP! I'll do anything in return! Read your book, edit some of your book, whatever you want! Or if you just love me and I don't have to to anything.. that'd be great too.. :)

You can view Flawed here.