|Hello, I came across your piece as a random read. I don't often review chapters, but I too have been working on a book and so I'm trying to expand on the types of reviews I do.
An opening chapter should grab the readers attention. I think yours does that, at least the opening line. You know there is tension, someone is angry and we, the reader, are interested to know why.
I can see that you are trying to include descriptions in your writing, this is good, however, we need to be careful that don't describe everything in the same way. For example, "my small, cramped bedroom", "my brown, wooden door", "the wooden, creaky stairs". I still find myself struggling with how to describe the scene. Perhaps, try to shake it up a bit. Instead of telling the reader, "I did this, then I did this", try to rearrange the sentence structure a bit. "The bed springs creaked as I rose and reluctantly approached my bedroom door." (Although, I use words that end in -ly, we are often encouraged to use them sparely, if at all. It will make our writing stronger.)
Another thing to consider, is the character description. Many writers do as you have done and literally stand them in front of the mirror, simply to examine the features that they have seen for years. It's ok not to have a complete physical description in your first chapter, although I do like to know if the main character is male or female. A general age is nice, I'm guessing your character is younger, (teen or young adult) since it seems that they live with their mom, but of course there could just as easily turn out to be some reason. She has a key and lets herself into his house, whatever.
After the main character gets downstairs and sees his mom, I think you could leave out the part, "When I looked," and just say "Behind her two burly-looking police officers..."
As far as the plot, there's not a lot there, but you have already dropped the reader into the action as it were. This is good. Something has happened to involve the police, and we are intrigued to know what.
I hope I have been helpful. I don't like to make assumptions about writers but if you are still new to writing, the best advice is to keep at it. It's like a muscle, the more you use it the stronger it gets. And read, read lots of books. Good books can teach you how to express the ideas in your head. Bad books can show what not to do, and how painful it can be to read them. So keep it up.
P.S. I gave you 2.5 stars. In general, it's best to pay more attention to comment then the number. I gave the rating I did, because your chapter still seems to be in its early stages. If you continue to work on it, I could always give you my thoughts on any updates.