Infinite In Between by Carolyn Mackler

This book follows five teenagers who write letters to their future selves during freshman orientation and navigate four turbulent, interconnected years of high school before reuniting to open them at graduation. 

This book contains: alcohol/abuse, alternate gender/sexual ideologies, anxiety, body shaming, bullying, controversial cultural, racial and social commentary, death/grief, deception, depression, derogatory terms, drugs, explicit sexual activities/nudity, non-sexual nudity, parental neglect, profanity, sexism, smoking, theft,toxic relationships and verbal/emotional abuse.