The problem with the designation “coming of age” is that it often assumes there is a particular, identifiable moment when we finally discover we have “grown up.” Like the best coming-of-age chroniclers, Heather O’Neill understands that the border between childhood and adulthood wavers and breaks with surprising regularity, regardless of which side of the line you’re standing on.

O’Neill’s debut novel is narrated by Baby, the 13-year-old daughter of single father and heroin addict Jules. Throughout her young life, Baby is shuttled between various run-down Montreal apartments and foster homes, and spends a month in juvie for hanging out with a pimp in the park. Baby’s story, episodic in form, unfurls in the arbitrary, unscripted manner of “real life,” with none of the archetypal, cut-and-dried bad guys you might expect from an account so steeped in street-kid tragedy. Jules can be a neglectful creep, and Alphonse, Baby’s abusive boyfriend, has his genuinely sympathetic (and pathetic) moments as a character.

There is a wonderful wryness to Baby’s voice that never stretches beyond her years and that offers a measure of ragged hope. With a perfect blend of heart-rending naïveté (“There were a lot of things that I did that I felt funny about”) and hard-won wisdom (“As a kid, you have nothing to do with the way the world is run; you just have to hurry to catch up with it”), she notes the loser kids and misfit adults who surround her even as she takes her place among them. Baby’s plainspoken yearning reminds us that maturity has less to do with getting older and more to do with how we transform our experiences into stories we can bear to carry forward.

This is a nuanced, endearing coming-of-age novel you won’t want to miss.