Star Rowe, an 11-year-old from San Francisco, stopped by yesterday to promote her new book on U.S.-Soviet relations called "Making Friends." Michelle Alexander, also 11, was in town from Fresno, Calif., with a copy of her board game, "Give Peace a Chance," destined for Soviet leader Mikhail Gorbachev.

And Heather Iliff, 17, coproducer of a videotape on American and Soviet students, left her Arnold, Md., home at dawn yesterday morning to meet a senior Soviet delegate at the Madison Hotel.

Welcome to the younger generation of U.S. arms control advisers who have converged on Washington this week, hundreds of almost ready-for-prime-time players wearing suits, carrying briefcases, passing out business cards and, occasionally, looking over their shoulders at adult sponsors as they pursue youthful political agendas.

These youths, most of them from junior high age up, resemble somewhat the blue-jean set of the 1960s, at least in their idealism. Adults, including their parents, still clearly influence the content and packaging of their ideas.

But it would be wrong to write them off simply as pawns of a frustrated generation of peaceniks. There are too many of them for that, and those who are here to argue against the arms race do so on their own terms, which are often economic.

"I don't believe a nuclear holocaust will happen in my lifetime," said Iliff, a model of poise yesterday in her black suit and magenta blouse. "But what bothers me tremendously is the amount of money both of our countries are pouring into" arms. That money, she said, could be better spent beefing up the U.S. economy.

Economic pragmatism fuels young activists today, and makes them open to peace initiatives, said Sanford Gottlieb, senior analyst for the Center for Defense Information who does a lot of speaking on high school and college campuses.

Iliff's group, Direct Connection, is one kind of youth group visiting the capital this week. Representatives from Youth Ambassadors, a Bellingham, Wash., organization that publishes a newspaper and sponsors camps in the United States and the Soviet Union, also were here with a chief financial backer, Henry Dakin, whose family makes a well-known and pricey line of stuffed animals.

A delegation of U.S. and foreign children presented roses hailing the new arms treaty to officials in the Soviet Embassy, and made a similar attempt, unsuccessfully, at the White House. Individual youngsters also competed for attention, including a 9-year-old girl who presented a letter to Soviet officials asking their government to relax restrictions on Soviet visits to the United States.

No group had an agenda quite as ambitious, however, as Direct Connection. Prompted by founder Michael Killigrew, a painter from Grass Valley, Calif., the 12 students are quite specific on what they hope to accomplish.

They want to show Gorbachev and President Reagan their correspondence program with Soviet youth. They want to sit down and discuss their views on war with the Soviet Central Committee. Most of all, they would like Gorbachev and Reagan to speak to young people specifically as part of their final press conference today.

They have no idea whether they will accomplish any part of their plans, for earlier attempts this week by other youth groups to reach either of the superpower leaders have failed. Aware of Soviet attempts to project a favorable image in the U.S. and Soviet media, they're pinning their hopes primarily on Yevgeny Velikhov, an arms control adviser to Gorbachev who has actively encouraged exchanges of American and Soviet youth.

"I think the chances for something happening are quite good," Velikhov told the students yesterday. They reacted in contained gasps of glee, then huddled with Killigrew to see what he thought Velikhov's remarks really meant.

Adults such as Killigrew are critical to the success of these youth organizations. He said the organization is run by students, mostly from high school student councils, although all of the correspondence he showed a reporter had gone out over his signature.

Sometimes, it was difficult to tell where adult participation ends and the children's begins. Michelle Alexander, wearing a sweatshirt from her group, "Children as Peacemakers," sat propped against a pillar at the Marriott Hotel's international press center yesterday.

She clutched a sample of "Give Peace a Chance," the game she invented when she was in third grade. "This is my game," she said proudly. "I created it. I won a prize."

Then she started to explain how it is played. "It's just like Monopoly . . ." she began.

"No," came a voice from behind her, from her mother Roberta. "It's the antithesis of capitalism."

Capitalism for some of these young people is not the dirty word it was for some of their parents. But, said Jay Plum, a young member of Direct Connection, it must be tempered with a concern for others. And, added Andy Leman, one of Plum's friends, growth for growth's sake is impractical. He counts Reagan's Strategic Defense Initiative as among the most impractical.

Leman, ribbed by his friends for his dark blue blazer, red tie and matching red handkerchief, said he and his friends at his high school in suburban Sacramento, Calif., are very much aware that they are part of a new generation.

They've never lived through a war, and in some ways that makes the possibility of war less real. But they've never lived without the threat of nuclear war, and that energizes some of them to work for arms reduction.

Polls have shown that American youth are growing increasingly fearful of nuclear war. A vast majority of teen-agers view the nuclear arms buildup as the nation's biggest problem, and this has led mental health experts to write about a sense of futurelessness among the youth. That sense was not found among the youth in Washington this week, perhaps because they are engaged.

"I know I can make a difference," said Iliff, daughter of an electronics engineer who left the U.S. Navy years ago for reasons of conscientious objection.

"If I touched one kid I met at {Moscow} School 72, and he goes on to become a peacemaker, I will have made a difference."

"A single hair casts a shadow," she added, hurrying off to finish arrangements for a car pool. Staff writer Saundra Saperstein Torry contributed to this report.