PORTLAND, ORE., AUG. 23 -- At age 16, the National Women's Political Caucus (NWPC) is at the awkward stage. The organization, with its state affiliates, has established itself as the principal support network and training ground for progressive women candidates at all levels of public office. It has survived the skeptics and critics of its early years, but as its biennial convention ended here today, it was evident that its development, like that of other teens, is still quite uneven.

"We've had our early-growth spurt," said Irene Natividad, reelected without opposition today to her second two-year term as chairman of the 77,000-member organization. "Now we're in our growing-up years, and we realize that it will take more than enthusiasm to reach our goals. It will take professionalism."

The 1,000 delegates cheered the prospect that a long-cherished dream, a woman running for president, may be realized next month if Rep. Patricia Schroeder (D-Colo.) declares for the Democratic nomination.

At the same time, they prepared somewhat grimly for what may be an uphill battle against Senate confirmation of the Supreme Court nomination of Judge Robert H. Bork, whose elevation they fear would jeopardize the "right of individual choice" on abortion, which has been one of their main objectives for the last 16 years.

The paradox of breakthroughs versus rear-guard battles on both political and policy fields confronted them at every turn.

At the opening ceremony Friday, more than a hundred elected women officials filled the stage of the Schnitzer Theater and stepped forward, one by one, to deliver brief messages in strong, confident voices. The delegates cheered Gretchen Kafoury of Portland, who identified herself as the chairman of the Multnomah County Board of Commissioners, composed of "five proud, female feminists."

But they groaned when Lt. Gov. Evelyn Murphy of Massachusetts said, "Despite our state's wonderful, progressive tradition, I am the first woman ever to be elected to anything statewide in Massachusetts."

The group's increasing clout in Democratic Party politics was dramatized by the appearance of five of the eight declared and prospective presidential candidates and the active proselytizing by supporters of all eight.

On the other hand, the Republicans who have stayed active in the NWPC since it endorsed the Walter Mondale-Geraldine Ferraro ticket in 1984 said they felt more and more isolated and alienated from their party. Not only did all the GOP presidential hopefuls decline invitations to appear, but the Republican National Committee sent no officer or staff member.

Mary Stanley of Fresno, co-chairman of the Republican task force, told a meeting of other GOP women that it was "a sadness" to her that Maureen Reagan "is the first co-chairman of the RNC in the last 16 years not to attend this convention. We endorsed her" when she ran unsuccessfully for the Republican Senate nomination in California in 1982 "and now she's ignoring us."

While "the old boys' network" is still perceived by female activists as the main reason that there are only two female senators and three governors, and women hold only 5 percent of the seats in the House and 14 percent in the legislatures, there is greater acknowledgment that women may be contributing to the problem.

A survey released by the caucus showed that older, married white women in the South and North Central states may be less supportive of women candidates than younger males and blacks in other sections.

The convention keynoter, Vermont Gov. Madeleine Kunin (D), told the delegates that the "most blatant forms of bias are behind us" and the most significant obstacles may be "the inner barriers" left by the attitudes of passivity and acceptance she said have been bred into women by generations of acculturation. "We are not fighting bias," she said. "We are truly building a new trend . . . . We cannot blame outside barriers alone for the small number of women officeholders."

To increase the numbers of women in public office, she said, "more women must move from the passive to the active voice. . . and take personal responsibility for making the changes we feel must be made. We need highly professional, well-financed campaigns, and when we have them, we can win."

The numbers of corporate lobbyists here suggested that one important source of campaign money is becoming increasingly accessible to women. And the 300 women who attended an all-day seminar on political polling demonstrated their recognition of the value of professional skills.

In the long run, those forces may prove to be more significant for the future of the teen-aged women's movement than the results of coming battles involving Schroeder and Bork that captured the activists' attention here the past few days.