When my youngest daughter told me in February that she wanted to accept a fellowship to assist a professor at her college over the summer, the impact of her plan didn't hit me right away. Only later did its import strike: When the last of the children isn't home for the summer, another of the primordial attachment strings is broken.

As each child leaves home, parents expect to go through an adjustment. We prepare ourselves for the inevitable, but then every change of plans that hastens the process hits us hard. This was supposed to be one last summer of mother-daughter outings and the like, but it won't be now that my daughter has adopted an accelerated schedule for growing up.

When our eldest daughter spent her first summer at school after her junior year, I was comforted by the noisy presence of her two younger sisters. Then when the middle one traipsed off on summer adventures, including working in a London hospital, there was still the youngest to fill the house.

But now even her time has come to fly a little further from the nest. And suddenly, what she told me about the summer research assignment that cold winter day has struck home, leaving a hollowness in the general vicinity of my heart. For now I realize that it's my time to do some more growing up and growing away.

Several weeks ago on a brief visit home, she provided a taste of what I would miss this summer: a clothes-strewn room, a permanently outstretched hand and a near-total appropriation of the car. Even the extra-loud music and late-night visits with friends made me realize that I would have had to make an adjustment from my more tranquil existence. Yet I'd also have had balancing agents: the laughter and jokes, the sharing of shopping trips and theater, the talk of music and politics.

Nevertheless, when one friend calls to say she is preparing for her daughter's summer arrival by vowing to be less self-sacrificing, and another friend is ambivalent about her son's imminent departure from Washington to wait tables on Martha's Vineyard, and a father is properly detached as his son goes off to work in California, I am in turn envious, understanding and incredulous.

Then a friend calls and asks, "Aren't you happy not to have to give up the privacy you now enjoy?" And another one wonders, "Won't you miss her?" And the answer to both questions is yes. I would miss my privacy, but I long for their company. I understand the need to let go, but I understand the joy of their homecomings. It's all part of growing up.

Still, irrational thoughts flit through my mind. Because I know this youngest child may join her sisters in never again living at home for extended periods of time, I doubt the strength of her preparation for life's complexities.

Have I taught her enough about self-love and self-acceptance? Does she know that it's good to take risks, including the risk of failure? Is she tough enough to define herself -- spiritually and intellectually? Does she know that to make it in this world she'll have to follow many a road in the wilderness, and does she have the tools for the task?

I know these thoughts aren't logical because parental teaching does not stop when kids don't come home in the summer. The telephone calls come frequently, as we talk of daily events and plans for the coming year.

A wise friend once said, "When your children are free, you are free." At first I did not know how difficult it would be to let them go, but I now know he was right. If we are fortunate as we snip the cord, however, the nature of the relationship changes and parents and our children can eventually become friends.

So for now, I know that while this twist in the plan was not anticipated, it's really part of the same rite of passage that began when she left home, and it is also life's way of pushing me -- to get on with my own growing up.