The characters felt very alive in this story! I also loved many of your descriptive tidbits, such as the line about the barrettes, and how Mark's glasses matched his braces. I think the dialogue bits could use a little work-- the dialogue itself is fine, but I found myself confused as to who was talking a couple of times. No worries though. :)
Also, love the bit about the "severed reproductive organs." I giggled out loud there.