The night before we left, three possible scenarios played through my mind. As I glumly packed my backpacks, listened to weather reports predicting sub-freezing nightime temperatures and contemplated the broken zipper on my cheap and plainly inadequate sleeping bag, I imagined:

SCENARIO ONE - The weather is beautiful and I, like a true child of nature, trip gaily up to the mountain top without even breathing hard.Once I arrive, squirrels, chipmunks and other woodland creatures come and eat from my hand. Little birds fly softly around my head, perching companionably on my shoulders and twittering songs of springtime in my gladdened ears.

SCENARIO TWO - I manage to go three miles before I fall gasping to the earth and must be ignominiously carted off like a helplesssack of coal by my humiliated son and the four 13-year-old boys with us on the expedition.

SCENARIO THREE - I make it to the top of the mountain, where I get frostbite, or break a leg, or a combination of the above and must be tied to a rope dangling from a helicopter and airlifted to the nearest hospital.

Why, I wondered as the time for departure drew near, had I agreed to accompany my son on the backpacking trip for 12-to-14-year-olds sponsored by the Howard County Department of Parks and Recreation?

Actually, Howard County's wilderness program is an innovative one offered by few other jurisdictions. A less rigorous form of the "Outward Bound" programs, it's intended to foster qualities as responsibility, group sharing and self-confidence in kids.

In a parent about to go on a trip, however, it fosters dread. Let me say right now that I am not the athletic type. In grade school, I was the kid who always stumbled at kickball, who wouldn't chin herself and who chickened out when the pole got to the two-foot mark at high jump. My memories of gym feature mainly images of humiliation and inadequacy.

When my son and I went to the county's pre-trip meeting, I learned that we would be climbing Old Rag Mountain in the Shenandoah Valley. I also learned that we would not be spending the night, as I had naively imagined, in some conveniently located log cabin with a charming rustic fireplace, but under a tarp.

At this point I began to be somewhat apprehensive. For one thing it was turning out to be a cold spring, with temperatures going down to freezing and below. How warm are tarps? For another thing, it began to dawn on me that this was going to ba a seven-mile walk uphill carrying a weight on my back. Could I do that? I wasn't so sure, I'm the type who always takes the elevator when there's more than one flight of stairs to climb.

At the pre-trip meeting we were introduced to our expedition leaders, Beth Marshal and Ken England, both extremely healthy-looking young people who seemed quite unperturbed about spending the night out on top of a mountain.Indeed, Beth, I learned, planned to spend the summer in Alaska climbing glaciers. Climbing glaciers? Wait a minute!

But it was too late to back out. I had already bought a backpack for may son and rented one for myself from Appalachian Outfitters ($5.50 for the weekend). My son had reached a fever pitch of excitement and had bragged about the trip to all of his friends.

"Hey, guess what? My mom is going to take me backpacking! Isn't that neat!" How could I dissapoint him?

So what was it really like?

When the trip was over Beth asked us to name three words that best described the weekend. The boys had no trouble with this. They immediately came up with "beautiful," "challenging," "scary," "exciting" and "fun."

But I couldn't find the right words for me and asked for some time to think it over. I've been thinking about it ever since. "Grueling" would certainly be an appropriate word - for me the trip was tough. Old Rag Mountain is a real mountain, and a lot of the six to seven miles I had visualized as a pleasant walk in the woods was actually straight up over rocks.

It was exhausting. I guess that's why I ate so much of that darn "gorp," a food mixture that hikers and backpackers use for quick energy. When things got tough, which for me was often, it was very comforting to grab a handful of gorp.

The trip was emotionally as well as physically grueling because I often had to do things that frightened me. The top of Old Rag involved quite a bit of rock-climbing. I was not prepared for this, and some of it looked pretty impossible to me. But I'm proud to say I did it - though there were times when Ken and Beth had to get behind and push.

"Liberating" is another word that seems apt to me. I hate to use that old cliche about looking down from a mountaintop and realizing how petty the things that have been bothering you really are. But after all, the reason it's such a cliche has got to be because so many people have found that it accurately describes this experience.

When you look down at the world from a mountaintop, you really do get a different perspective on what is and is not important. I guess it's good to do that occasionally.

The trip was liberating for me in another way. I got to stop playing mother for a while. Ken and Beth were in charge of the expedition, not me. My son and I were just fellow travelers for a change. This mean that we enjoyed a different relationship from our usual one. I'm glad we had a chance to do that, and I hope we get to do it agains sometime.

I spent a lot of time wondering what the last word should be. I think it has to be "enlightening." I learned a lot of things, about myself and about others, on this trip. For one thing, I learned that it's a lot of fun to listen to 13-year-old boys sit around a campfire and tell jokes and stories to one another. I don't think I knew that before.

The boys who went on the trip were nice, high-spirited kids who laughed a lot and genuinely enjoyed the experience. They even laughed when it started to sleet on us in the middle of the night. What astonishes me, as I reflect on it now, is that because they thought it was funny, I began to think it was funny too.

The other part of the enlightenment had to do with my finding out about me. I learned that I'm not as much of a a sissy as I thought, and that makes me feel good.

In seven year, Howard County's Wilderness Program has served nearly a thousand kids. Its brochure says, "Risk-challenge is a concept at the heart of the program.

"A number of activities are presented involving some physical and emotional risk - all challenge the individual to fully use his existing resources. By attempting a graduated series of these activities and succeeding in a supportive group atmosphere, participants can increase their self-esteem.

"Anyone who conscientiously tries is respected; success or failure is less important than making a true effort."

Because of the element of risk involved, few county recreation departments are willing to undertake this kind of program. To learn more about the one Howward County runs, call 301/992-2480. CAPTION: Picture, THE TRUDGE UPHILL, FUELED BY GORP.