Too fast :(
If you're gonna make a character who's accused of steroids make somebody above the age of fifteen. Most people don't like reading about a thirteen year old who uses drugs (or accused), but I like you setting the age at thirteen.
You went too quickly, on something I felt could have gone way better! Let's find out how his parents reacted to the accusation. He didn't show lots of emotion either :(
I just feel you were rushing yourself to create a story, which I have to call cute, but you should have hung onto it for maybe a week while you tweaked at it here, and changed it around to make it a grand story that let's the reader grasp onto the character and then gasp when their hero is accused of such a travesty!
When you write, keep yourself patient, hang onto the story for a while, and think of your character, and the characters around him, and then you'll get a "snap" moment when you go "I want this to happen too", and like that you'll give it a great plot, and character definition.
Good luck, can't wait to see your next work.
(review of free book)