My plane is at 33,000 feet somewhere between Illinois and Washington. I feel like a mother bird who plucked her "baby" out of the nest, flew as far as the wind blew and then dropped her, ready or not, to see if her wings could hold.

Three hours ago I said goodbye to my oldest daughter on the Washington University campus in St. Louis, Mo.

"I can't wait with you for your cab," she had said. "I'm afraid I'll cry."

When she turned and walked back to her dorm I thought she would look back, and I could wave. But she didn't. I knew she had to get to the privacy of her room fast, just as I needed to get back home and make sure everyone was still there.

I have five children and a new dog. I think that's twice the national average for family size. So why do I feel so empty and alone? I have always been casual about their milestones in school.

When they went to nursery school I couldn't wait until kindergarten. Mothers who cried on the first day of first grade amused me. I thought I was a tough mom with a heavy work load.

For 18 years I've worked for my children's growth and independence, yet I somehow managed to block out their leaving home.

I am well aware that in these times of economic hurdles the tradition of the college graduate getting a good job and settling down somewhere 900 miles away from home is almost extinct. My friends who are "boarding" their grown children warn me I'll rue the day the kid comes back looking for a meal.

But . . . this is my first goodbye. I can be hard-nosed and crusty 10 years from now when all five children have left and the first are heading back with laundry and lover in tow. Right now I no longer laugh at the empty-nest syndrome. I lament the nest emptying.

The worst part is my feelings are so mixed. While I'm sad at Lisa's leaving, I'm proud of her efforts and envious of her opportunities. Today I wanted to stay and enroll so I, too, could walk through ivy-covered archways.

Last year after pouring over Lisa's college catalogues I began toying with the idea of finishing up my degree, something I've been defensive about for 20 years. So it was no fluke that Lisa and I attended a summer lecture at Georgetown University on "Cultures of Antiquity." That night in a small classroom the two of us sat like clones while the teacher charmed us both with comparisons of Kant, Aristotle and Dante.

"I can't wait to learn more about all this stuff," Lisa commented as we drove home. "Neither can I," I murmured.

Consequently, I start a class at Georgetown in three weeks. For as the children grow, I have more time to grow intellectually. Besides, not only do I want to learn, I want to keep up with my children. When they come home to argue philosophy and politics, at least it will be a fair battle.

Two weeks ago the whole family went to the beach, just as we have for the past dozen or so summers, only this time I spent the first two days--like an over-protective new mother--monitoring my eldest's every move and mood, as if I needed to memorize her presence. She, in turn, withdrew or became "touchy" whenever she caught my concern. It was clear I was driving her crazy, and we both needed to start stepping back before saying goodbye.

I took to the beach, and for hours I sat under my umbrella like a sentimental Margaret Mead, observing parents and all the different ways they handle their children. My favorite sighting was a red-bonnet, shirt-clad toddler hanging on for dear life to her father's single finger as together they dared to let the waves come just to their toes.

Just wait 17 years from now, I told myself, that father will want just a moment of a fingerhold, and his daughter won't be anywhere in sight.

But this is getting too melancholy. What were all those 18 years of labor and love about--but to prepare my child to be on her own? So I'm going home, my dear. I know I'm not "losing" you or abandoning you, you're just changing. That's all.

Remember when I first discussed this article with you? Realize, I said, that it may expose our personal feelings and experience.

"Don't worry about it Mom," you said. "I won't be here to read it."