BY JUD COST

"'What a drag it is getting old.' And yet, here we are," chirped Go-Go's lead singer Belinda Carlisle, quoting a line from their sandpaper-tough cover of the pill-popping Rolling Stones classic "Mother's Little Helper" to an excited full house at San Francisco's storied Fillmore Auditorium.

On the 30th anniversary of Beauty And The Beat, the radiant debut album by the Go-Go's, all five originals - Carlisle, guitarists Charlotte Caffey and Jane Wiedlin, bassist/guitarist Kathy Valentine and drummer Gina Shock - have reunited to show their fans they've still got the beat. To be honest, having seen the girls three times back in their 1980-82 heyday, they sounded better than ever tonight. Plus, it was a chance to feel like you were 21 or 31 (or 11) again for just an hour and 15 minutes. The crowd seized the opportunity like a pit bull shaking a rag doll.

The Go-Go's kicked off a fun-filled evening with "Vacation," whose endless-summer boundaries seemed as welcome as that feeling a teenager had when June rolled around. Ninety days seemed like forever back then. Oddly enough, this show coincided with the opening of school in many Bay Area locales, right in the middle of August. A few Caffey-coiffed moms with their pre-teen daughters in tow were playing a dangerous game, allowing the kids out on a school night. Maybe they could justify the Fillmore show to school officials as a hands-on history lesson, showing the sprouts the headlands of feminist rock 'n' roll. After all, without the Go-Go's trailblazing efforts (and those of Patti Smith), the early-'90s blitz of the Riot Grrrl phenomenon that included Sleater-Kinney, Bikini Kill and the Breeders, might never have happened.

"We have our own star on the Hollywood Walk of Fame now," said a snow-white thatched Wiedlin, reminiscing briefly about how the Go-Go's assembled in Hollywood from far-flung ports to start life anew as a punk band at famed L.A. basement club The Masque in 1978.  They cranked out "three chords and a cloud of dust" number "Fun With Ropes" just to prove it. But it was "This Town" that more accurately portrayed life on the Go-Go ("This town is our town, it is so glamorous/Bet you'd live here if you could and be one of us.") It's lyrics somehow blended a generous, egalitarian ethic with just a dusting of well earned "nah, nah, nah, nah, nah, nah."

A brilliant cover of "Cool Jerk," a 1966 smash by Detroit R&B outfit the Capitols, let the crowd swing its arms in an intentionally awkward fashion while a couple of scruffy Go-Go Boys flanked the band with the same kind of flailing moves. The biggest crowd response, of course, came from Go-Go's smashes "We Got The Beat," and "Skidmarks On My Heart," a cautionary tale about a grease-monkey boyfriend who spends too much time working on his car ("You're burning rubber like my heart"). The android-like "Automatic" may have inspired the similarly mechanical "Walk Like An Egyptian," the 1986 national smash by fellow Angelenas the Bangles.

The expanded CD reissue of Beauty And The Beat (Capitol/I.R.S.) sports a second disc full of live gems, including a ripsnorting version of "London Boys," a brisk instrumental medley ("Surfing And Spying'"/"Beatnik Beach") and a spine-tingling reading of the Shangri-Las' "(Remember) Walking In The Sand" with the girls soon abandoning the ultra-dramatic pace of the original to break ranks and go for broke.

A pair of sharp solo numbers by Carlisle ("Mad About You") and Wiedlin ("Cool Places," cut with the Mael brothers from Sparks) were a perfect fit tonight with the full-band material. Like a BLT sandwich, the Go-Go's sound has never been a mystery, just an excellent mix of basic elements. Add a solid base of Duane Eddy/James Bond soundtrack big-guitar moves, a few well chosen New Wave minor chords and a marvelously harmonic vocal blend to a stringent, Tinseltown band-admissions standard with extra points awarded for the "cutie pie" factor - exactly what the brand new MTV landscape needed 30 years ago - and you had a band that seemed like  it might go on forever.

Looking like they'd aged only 10 or 12 years in the interim, the Go-Go's, if they want to be, are one solid new album away from being a permanent fixture on the concert landscape for the next decade, at least. Scratch that. They don't even need the new album. But it would be nice.