Chatspeak in your intro! Remove it! Chatspeak is to Writers as Garlic is to Vampires.
Okay, actual review now.
Who said what?
'Said' is a cool little word, in that you can use it over and over and it has a way of blending into the background. It's so commonly used that often your reader skips over it as they acknowledge the subject (HE said, said JACK.) Don't be scared of it. Here in your work you have a habit of glorifying your speach tags a bit too much, when really, their simple purpose is to tell the reader who is saying what. For example; "...I said, blowing it off as nothing..." or "...he said as he shook me..."
Just remind yourself every so often that the purpose of a word tag is just to clarify who's speaking (if you haven't already done so) and it will help break the habit.
Keep it together!
The speech, that is. Imagine someone has run really fast in order to tell you something, and because they're out of breath it takes twice as long for them to tell you in between gasps of air. It's annoying. That's what it's like when you put strange pieces of description or action in between pieces of speech. Wherever you can, keep all the speech together, unless there is a purposeful long pause in the sentence.
Chapter One:
This is an average chapter, in that, it would fit somewhere in the middle of a novel. It's not really material for a crucial scene, but it's too good to consider chopping. That said, your first chapter needs to be gripping. The average novel takes about twelve hours to read, so the sooner you can get your reader and your main characters acquainted, the better. Here, you haven't really introduced these characters, and it feels like I'm reading a random chapter rather than starting at chapter one.
The step-dad...
Is a jerk... But he seems lacking. Even evil step-fathers need a motive to beat up their step daughters, and they generally don't waste their breath talking about random things or using expressions like 'we were worried.' Phrases like that are usually used as cover ups to play the nice parent role, not as an excuse to the victim. He needs some kind of provocation, or perhaps a hint that he has been playing things out in his mind for a little too long.
Overall:
This is a good piece of work, but as I said, not really first-chapter material. Hope this helps
And now on to chapter two.