Q.My 11-year-old's life is full of activity, but it's not full of friends.

Her father and I always knew that she didn't make friends easily, but now she's in the sixth grade and this is beginning to hurt her feelings more and more.

The boys who had been her friends began to back away from boy-girl friendships last year so now she has no one to pal around with at school or afterward.

Although she runs cross-country, plays piano and bells, goes to church and Sunday school, and enjoys all activities, she is more interested in her toys and in imaginative play than in pop music and cool clothes, and she loves to read and to play by herself most of all.

We think she is also quite cute -- in a boyish sort of way -- and know that she is very, very bright and passionate, too -- a person whose feelings are easily hurt, which can make her seem quite fierce.

She doesn't usually feel the lack of a friend until her brothers, 9 and 7, have their buddies over and then she belatedly calls around looking for someone to hang out with. Sometimes she strikes it lucky, but by then it's late afternoon and the other girls are usually busy, which leaves her heartbroken.

We've tried to encourage our daughter to be a better friend to others but we suspect she is often lost in her own world and oblivious to children at school.

Her teacher says that the kids are friendly to her and that she isn't a "loner," but we've chaperoned her class dances and know that she is just not part of the crowd.

I know that she will eventually make friends with people who share her interests, but that could be years away. What should we do in the meantime?

A.Never do differences show up more clearly than they do in the sixth grade.

Many of these children are growing up, inside and out, wildly, differently and rapidly.

Some will spurt up six inches in three months, making the rest of the class seem shorter than ever, and others will begin to think in abstractions, making intellectual leaps far ahead of their classmates. And then, of course, there are those hormones that make the chests of some of these girls look like they've sprouted two little hills, while others remain flat as Kansas.

All of these changes tend to divide the class along new lines, making old friends split apart as new friendships follow new interests.

Perhaps nothing affects sixth-graders more than the difference in their social skills, especially between boys and girls. Some boys are still telling fart jokes while the girls are rolling their eyes in disdain. And some girls and boys wonder how to make one friend, while others gather them up like flowers in a field.

Don't push your daughter faster than her own nature wants her to go. It's better for her to find a couple of friends who are right for her temperament and her interests than for her to make many friends just for the sake of making them.

You can help, though. Notice which girls your daughter likes and then encourage her to invite one of them over to watch a movie, bake brownies or shoot some hoops, but don't let her wait until the last minute to make that phone call. Children are usually too busy to accept last-minute invitations.

You also want to encourage her to make friends through volunteer work. She can bring some of those brownies to an old lady at a nursing home or simply visit her once a week.

A variety of friends, of all ages, inevitably enrich a child's life and broaden her perspective.

And finally, ask your daughter to reach out to a child in her class who needs a friend even more than she does.

The friendship we offer to others makes it easier for others to be friendlier to us.

For more help, your daughter may want to read "Popularity Has Its Ups and Downs" by Meg F. Schneider (Simon & Schuster, $9) and you may find some good tips in the "Making Friends" section of a book called "Good Friends Are Hard to Find" by Fred Frankel (Perspective, $13.95).

Questions? Send them to advice@margueritekel- ly.com or to Box 15310, Washington, D.C. 20003.