FROM THE MOMENT I walked into the Nassau Coliseum, a blockhouse-like structure surrounded by a no-man's land of lights, fences and police, I knew I'd found the answer to a question that's been puzzling me for a long time. Joni Mitchell's concert that night, part of a massive world tour, was to my mind a pleasant diversion. But to the thousands of young kids (especially teenage girls) in the audience, the two hours they'd spend with Joni were more a pilgrimage; a visit to Mahara Ji, a chance to peek into their own dreams. The question was seemingly a simple one. Where are all the world's beautiful, ripe 14 year old girls? Where are all those Lolitas we've all heard so much about, with their pert tits, hard bums, yadda, yadda yadda? The answer? They're home listening to Joni Mitchell albums, of course.

Thinking about this revelation for a moment, it all seems too clear. These are the girls of the suburbs. No one can convince me that pretty girls live in the cities anymore. Their parents have all high-tailed it to suburbia or Vermont. These girls are living in the old plastic wasteland, and the older boys they crave move so fast when freed that Lolita and her sisters have nowhere to go but home to the Sony system, where even their parents are soothed by Joni's delightful voice, her stirring sentiment, her touching inability to stay in love.

Joni's songs have always been the stuff of which adolescent dreams are made. 'I Had a King' from her very first album was the romanticism of the girl from Freeport who finds love at an IND stop and moves into a railroad flat on East 5th St. Joni may have found a king; most girls from Freeport find speedfreaks. Then there were 'Clouds' and 'Chelsea Morning' and the now-momentous 'Ladies Of The Canyon', which pointed to LA as the place where the streets were paved with female fullfilment for all Joni's growing listeners. By the time of her third album, Joni had grown, if not to complete womanhood, to at least an inkling of her own self-sufficiency, couched as it was in the counter-cultural garbage of making cookies in the canyon.

After that came Blue. As more people than you can imagine already know, Blue is the best album ever to help you rationalize utter romantic defeat. It's the perfect "just got home from a one-night stand and the bastard/bitch didn't even cook me eggs" LP. For The Roses followed on a new label, David Geffen's Asylum, and people began to assume that Joni was caught up in the frantic El Lay life of popstars and lollipop swimming pools. What a fantasy figure Joni Mitchell had become! Her cheekbones haunted every college boy's heart. Her songs of grown-up disillusionment wormed their way into the psyches of the Nymphet Brigade. And she put it all together into such a class act that no one, but no one could dump on it. You had to know that none of the men she allegedly played with could hold a candle to her in the Classtakes.

If Court and Spark, Miles Of Aisles and The Hissing Of Summer Lawns then proved a bit confusing to those hung up on pretty melodies and sad lyrics, it was only because Joni had abandoned her little girlishness to become a woman with the same romantic notions and the same musical ability to get dumped on. This was the Joni who took the stage that night at Nassau.

The opening set by the L.A. Express (minus Tom Scott) would have been commendable in a midwestern cocktail lounge. At Nassau it provided the kids with an excuse to cruise the aisles. Overwhelmingly female, they seemed somehow subdued; well-behaved compared to the city audiences most performers face. One girl let out a freedom-seeking yodel and six cops' heads snapped to alert. No one picked up her cry. It was Clean Teen Night at Nassau, marred only by the predominance of emanciated young men in open-to-the-pupik dacron shirts and hanging brass Zodiac medallions.

Impatient stomps died out in ten seconds, changing to shrill screams as the lights around the black-wreathed stage went down and Joni stepped out to sing. She wore mandatory El Lay hip garb: black slacks, padded-shoulder jacket and slouchy hat. She opened with 'Help Me', looking like a soft David Bowie, singing in the best voice I've heard her in since Newport in the '60s. The set covered her career well, though it was heavy with her recent work. She seemed in total control, and the crowd sat munching her words and images like special, sweet Hostess Twinkies of the heart. Her between-song chatter was more coherent and less generous than in the past. All in all, she came off as a self-assured woman, a masterful entertainer, an eclectically brilliant composer, and the possessor of two of the finest instruments in popular music: a great set of pipes and those wonderful, vulnerable cheekbones.

The little girls went home, back to wherever the crunchy granola set go between MOR pop concerts. Their dreams were intact. It was all that mattered.