Where’d the time go?

Judy Collins is 72, a long way from the young folk singer who released “A Maid of Constant Sorrow” in 1961 and who covered Sandy Denny’s haunting “Who Knows Where the Time Goes” as the B-side to her 1968 hit recording “Both Sides Now.”

Her life can be viewed in terms of those three songs – and she probably wouldn’t mind if you threw in a little “Send in the Clowns,” as well.

“It’s always been hard,” says Collins, who comes to the Bing Crosby Theater next Thursday. “Any artist who tells you it’s easy is lying to you.”

Born and reared in Seattle, Collins studied classical piano as a child and made her debut there as a 13-year-old prodigy. But a growing interest in folk music earned not just the disapproval but outright scorn of her teacher, Antonia Brico (who, years later – even after Collins had an international singing reputation – told her: “Poor Judy, you really could have gone far”).

Sparked by the music of Woody Guthrie and Pete Seeger, Collins quit the piano, took up the guitar and joined the likes of Bob Dylan, Joni Mitchell and Richard Farina in the singer-songwriter-activist arena.

“You have to do what you have to do,” she says. “I tried to live up to my family’s expectations, studying my music, tending to siblings, being the good daughter – just doing what had to be dealt with growing up.

“It turns out it was great training for the rest of my life.”

By her late teens, Collins was a street musician, busking in Greenwich Village.

One evening, while playing in a small club, she caught the ear of an Elektra Records representative and was offered a contract. Her debut album was “Maid” in ’61.

Stardom wasn’t made quite so easily.

“If you don’t want to work hard, you don’t want to be an artist,” she says. “It’s not going to be stardom in a week. A friend of mine who’s a writer says it’s like laying pipe. It’s work. And it’s not for everybody.”

The music scene in the ’60s and ’70s was exciting. There was a lot going on: musical, pharmaceutical – and sexual – experimentation that led to much discovery, some disappointment and more than a little fine art.

Collins’ 1967 album “Wildflowers” is a folk landmark. “Who Knows Where the Time Goes,” which came the following year, featured guitar work by Stephen Stills, with whom she was romantically involved. She was the inspiration for his Crosby, Stills and Nash classic “Suite: Judy Blue Eyes.”

Romance is one thing. Drugs is another.

“There was a time when a lot of people spent a lot of time and a lot of money doing drugs in the recording studio,” Collins says. “That wasn’t for me, and that’s not the standard operating procedure anymore.”

Though her fortunes and popularity have risen and fallen, Collins has worked diligently for 50 years now. This year alone, she will perform more than 100 concerts in the U.S. and abroad.

She composes music, she sings and she writes books. She also keeps a sharp eye on the business of being Judy Collins.

“Everybody who’s an artist has to fundamentally understand what’s going on in her finances and have input,” she says. “I’m very hands-on with what’s going on.

“You get lots of advice but ultimately, it’s your decision. Sometimes you get great advice, and that’s good. Sometimes, the advice is … not so good.

“I always say my mistakes are always $40,000 mistakes. That seems to be the cost every time.”

These days, Collins is the busiest she has ever been. October saw the release of an autobiography, “Sweet Judy Blue Eyes: My Life in Music”; a children’s book, “When You Wish Upon a Star,” companion to last year’s “Over the Rainbow”; and a new CD, “Bohemian,” which features many new original songs.

“This is definitely the best time of my life,” she says. “I’m the happiest, healthiest, most optimistic that I’ve ever been. There’s a lot of water over the dam. But I’m happier than ever, more productive than ever.”

It’s here the lyrics of “Who Knows Where the Time Goes” seem especially appropriate:

“I will still be here. I have no thought of leaving. I do not count the time.

“For who knows how my love grows? And who knows where the time goes?”