"MOM!" said the resident teen-ager in a voice hovering somewhere between a shriek and a hoot, "I DON'T BELIEVE IT! YOU WANT TO GO TO A ROLLING STONES CONCERT?"

A mother who has been living with a teen-ager for any length of time learns to tolerate all manner of bizarre responses, but that touched a raw nerve. After all, mine is the generation that included our Beatles and Stones records in our first divorce settlements. "Who," I responded with as much restraint as I could get on short notice, "in blazes do you think invented the Rolling Stones? I was listening to the Stones before you were born."

In fairness, I should note here that I can understand his amazement in that I had never expressed the slightest desire to see a rock concert before. And I wasn't much help in explaining why I wanted to go. "I just want to. That's all. And," I said, "I bet a lot of other people my age are going to want to go, too."

Without getting into specifics about what age we are talking about, suffice it to say that my son at one point saw himself going to the concert with the only person over 30 in the entire Capital Centre. While I had some sympathy for generational discomforts-- having had them at one point myself -- I was not about to let sympathy get in the way of my seeing the Rolling Stones. The maternal code of conduct calls for you to be selfless with your love, but it says nothing about being selfless with Rolling Stones tickets.

Proof that his mother had not gone completely around the bend came at the dentist's office when my son, under the influence of gas, began laughing and telling our dentist and his assistants about his mother getting tickets to a Stones concert.

"What," asked the dentist, drill in hand, "is so funny about that? We got eight."

My son's misgivings seemed to diminish as reports filtered in from across the country about the Stones attracting what is known as an "older crowd." A colleague who saw them in Detroit reported back that there had been a lot of people over 30 in the audience and he had even seen people with their kids. We pointed out television news clips showing people waiting in lines for tickets with babies in their arms and children by their side. I was affronted enough, however, to indulge with considerable glee in an excercise of unadulterated sadism. Not until late last week did we inform him that his father, who my son knew was not going, had purchased three tickets, not two, to Monday's opening night. That would not only spare him the onus of sitting alone with his mother, but also enable him to take his girlfriend. The epic generational struggle ended with a jubilant phone call to the young lady and the expedition was on.

Why did I want to see the concert? Part of it had to do with the feeling that I ought to see a modern rock concert and part of it had to do with nostalgia. This was, after all, going to be the Stones' last stop on their last American tour, and if you are in on something at the beginning, it's somehow nice to be able to be there in the end. And if they came to represent the dark side of rock and roll, well, there's a little dark side in all of us. It was a night to suspend judgment and have fun.

There would be, I was warned, a lot of dope. "Rowdy" was the unanimous prediction about the crowd. "Wouldn't it be funny if Mom got lit on the smoke and started giggling," said my son as we neared the Capital Centre. For the record, there was a lot of dope, Mom did not get "lit," and the crowd was not rowdy. There were a lot of older people there, including parents who went with their kids, a fact duly noted by my son the minute we saw people getting out of their cars in the parking lot. "See?" I said, triumphantly. "What did I tell you?"

For the uninitiated or for those who were initiated years ago and have since moved on to higher callings, some observations on concert going: the uniform is haute casual, preferably jeans; you are frisked for alcohol and dope on your way in; girls are not frisked as carefully as boys, therefore contraband is smuggled in by girls. The handshake method of dope transactions has not changed and joints are still rolled the same way they used to be. Lines at the ladies' rooms are three times as long as lines at the men's rooms, so if you are a woman, it is best not to drink beer. If you must indulge, however, it can give you a real thrill.

"May I see some I.D.?" said the young woman taking my money.

"You've got to be kidding."

"Twice they've asked me for I.D. and I'm going to be 40 in January," said a man smiling broadly.

Concerts also do not start on time, but by the time the Stones came on no one seemed to mind. They were sensational. It was the quintessential Event, celebrated by a standing, cheering crowd that moved with joyful abandon to the primitive touch of the music. For more than two hours, that's all there was -- Mick Jagger, looking older, but never standing still, as awesome an aging athlete as he is a performer, and the music. In the end, the audience wanted more and they applauded and then they lit matches and lighters and thousands of tiny lights flickered in the cavernous darkness. It was lovely. The Stones came out one more time and sang "Satisfaction," and for those of us who went for nostalgia and found a few moments of recaptured youth, that was the perfect ending.