Music is important. And it’s different for girls. That much is quite clear in Lavinia Greenlaw’s collection of brief essays that eloquently chronicle the myriad false starts of becoming on the path to growing up. It’s Greenlaw’s halting progress toward adulthood that is somewhat less certain. “I was wrong — standing in the wrong place and making the wrong shapes, the wrong noise.” In 1970s Essex, with no MTV to guide her, Greenlaw describes falling into one genre after another. Desperate to “learn to be a girl,” she flings herself headlong into Chopin and Chicago with equal fervor. Unlike boys, Greenlaw notes, girls aren’t inclined to discuss music or play air guitar. Instead they spin records as a soundtrack to their metamorphosis: putting up posters and ripping them down; squeezing into pencil skirts, then tossing them aside for garbage bags; screaming, crying, spraying their hair into winged helmets, then cutting it all off. Punk, for example, “didn’t just change what I listened to and how I dressed. It altered my aesthetic sense completely. This is what music could do: change the shape of the world and my shape within it.” A poet who has also written opera libretti, Greenlaw’s lyricism is constant throughout the changes she chronicles, whether evoking the thrum of the Sex Pistols or offering spot-on observations of awkward adolescent experiments. For those who came of age in the ’70s — and those who did not — The Importance of Music to Girls is a riff off a familiar theme, inviting us to sing along.