[TOMT][BOOK] Story about time travel and the $100,000 dollar pyramid.

The book follows a high school aged girl living with her mother in a shoddy apartment. The mother is employed as a defense attorney but would like to be a lawyer. There are constant references to the $100,000 Dollar Pyramid and to A Wrinkle In Time. I believe the crux of the time travel within the story is that the traveler cannot bring anything with them, including clothes (and paper in their mouth?). It seems the book also suggested that people walk through life with a veil over their mind and it's only removed close to once in a person's life. Edit: The time traveler may have pushed the protagonist out of the path of a moving car where he was then run over and left naked in the middle of the street