This is an interesting premise for a story. You do a good job bringing the reader in to Tanner’s thoughts and feelings. His love/hate relationship with mornings and absolute abhorrence of high school make him someone the reader can relate to. The dialogue between the characters and his internal dialogue has an easy flow. You give some good details, especially in Chapter 1, that help set the scene and bring the reader into the story. The description of the crowded hallways in school is a good example.
I was confused as to the extent of Tanner’s memory loss and how long he’s been suffering from it. I understand that the story is building toward a big reveal about the memory loss, but some of Tanner’s thoughts seem contradictory. For example, early on we learn that he’s blocked out everything and only knows that he’s 17 because that’s what he’s been told. A little later he’s describing the daily routine with his mother and how he loves her. Does he remember this woman and the maternal bond? Was the event causing the memory loss long enough ago that they developed that mother-son relationship in the aftermath of the trauma? Later on, over dinner, he can’t remember what happened at a recent visit to his father’s but then goes on to share a lot of background on his parents’ relationship with the reader. So maybe he doesn’t remember recent events, but he does remember his early childhood? I kept trying to figure out how extensive the memory loss was and it took me out of the story.
Keep going – you’ve got some good instincts with the characters, just don’t leave out the details for the reader.