"I never had any idea about how my life would turn out. But I remember thinking that this was the most exciting time in my life, a vital and expansive time when there was the general sense that you really could make a difference."

She was Mitzi Mallina then, the 20th person Sargent Shriver had hired when the Peace Corps was still a task force, and she lived on Water Street in Georgetown, sharing a riverfront town house with a half-dozen other young women out on their own for the first time.

In those early Kennedy years, the beginning of the New Frontier, everything seemed possible. And in the six years that the Water Street house thrived, though their names and faces changed -- altogether, 25 of them lived there on and off between 1961 and 1967 -- they symbolized that vanguard of young women starting to move into the professions.

"It was a very special time," says Mitzi Mallina Wertheim.

In the old days they'd called them "New Blood" parties because Milt Gwertzman, who worked for John and Bobby Kennedy, used to tell them he was going to introduce the Water Street bunch to a whole group of "new blood." It got to be a joke.

Eventually, they had "New Blood" parties twice a year. By then they were no joke, just fun, which is why at the 20th reunion party of the Water Street "inmates" Saturday night at the Potomac Boat Club, this poster was stuck on a wall:

"So this is what new blood looks like when it gets tired!"

There was a certain amount of taking "old blood" stock, which showed up in the name tags (printed with the words: "I haven't changed a bit"), on posters and in small conversation groups, like one near the bar ("So that's her husband -- not bad").

"Well, I'm in Los Angeles and I'm a mother," Water Street alumnus No. 1 told Water Street alumnus No. 2.

"And she has a swimming pool," No. 2 explained to a friend.

"Doesn't everybody in California?" replied No. 1.

And there was a certain amount of nostalgia, brought on by mementos from their salad days stuck around the walls, including a Life magazine spread that showed the inmates playing the official New Frontier game, touch football, rehearsing a chorus line number for a Hexagon Club benefit and entertaining boyfriends over a candlelight dinner.

Another memento was Tinka Gratwick Baker's letter to her parents describing the three-story brick town house, with balconies on every floor and such breathtaking modern features as bathroom scales that dropped out of the wall. The only drawbacks, wrote the $3,000-a-year Potomac School teacher, were the rent ($65 a month each) and the number of roommates (six).

"The whole setup was a bit like playing grown-up," said Baker of Washington, who finally left Water Street for New York to get a master's degree in Soviet studies.

"There was much naivete about our lives in those days. We were really just kids. Certainly the sexual mores were different. Relationships were more formal, unlike now. My kids share apartments with the opposite sex -- don't yours? -- and nobody thinks anything about it."

Nancy Thorpe Sellar, Suzanne Rodgers Bush, Clark Preston and Mitzi Wertheim, who still live here and look fondly at the Water Street house every time they drive across Key Bridge, started organizing the reunion back in April. They arranged a tour of the house (now owned by Continental Resources Corp.), the party at the boat club, a windup picnic yesterday, to which kids were invited, and tracked down everybody they could.

Only a few couldn't make it, among them a Zimbabwe farm wife, a diplomat in Brazil and a Colorado Supreme Court Justice. Among those who did was a contender for the United States Supreme Court, presidential assistant Elizabeth Hanford Dole, admitting that "it's nice to be mentioned" but declining to comment further on speculation that President Reagan may nominate her.

She was Liddy Hanford when she lived at Water Street the summer before she entered Harvard Law School, one of the North Carolina contingent working for their senator, Democrat B. Everett Jordan.

"Washington was like a magnet to me. I knew I wanted to live here because there were so many opportunities for women," she said.

In her third year of law school she wrote a paper on the constitutional rights of the mentally ill so that she could do her research at St. Elizabeths. Later, she was among 3,000 competing in the White House Fellows program and though she made it into the finals, lost out in the end.

"They were all political complexions," said Ron Wertheim, who was deputy general counsel of the Peace Corps when he proposed to Mitzi Mallina at the Water Street house.

"I went from the Peace Corps to the War Corps," said Mitzi Wertheim, who became deputy undersecretary of the Navy in the Carter administration and now is an executive with International Business Machines. a

While some of them worked in government, education, science and art, about a third of the Water Street crowd ended up working in the law. Some of those are getting into other fields.

"I'm not sure anybody seeing me knows I'm different," said Marilyn cohen, a San Francisco lawyer who recently has turned to writing, "but I'm bringing myself -- with a capital S -- back to Washington now."

Anne von der Lieth Gardner, another California attorney, said she has returned to Stanford University to get a Ph.D. in computer sciences.

Jeanne Presto, an artist and decorator while everybody else at Water Street was caught up in the excitement of the Kennedy era, has switched to legal services.

"Fifteen years ago I was putting up draperies in other people's apartments.

Today I want to be in the mainstream of what's happening, so in my mid-life crisis I've stopped painting to do legal aid work," she said.

To outsiders, they were the golden girls, with good jobs, interesting friends and attractive boyfriends, or as Suzanne Bush thinks, young women "blessed" by being part of that early generation when there was great hope and everybody was caught up in the spirit of it.

She married at age 32 two years after John Bush, sitting in front of her at church, turned to get acquainted.

"I had a lovely single life, but I'm happy now, too," she said.

She got the good job, administrative assistant to Sen. Jordan, "out of my system. I'm having a great time with two little boys. I'm president of the PTA, active in church. . ."

So what was so special about the house on Water Street? Was it an experiment in living or just an extension of the sorority house?

"What was so unique about it," said Mitzi Wertheim, "were the people. It was a warm, supportive, stimulating environment. We were out on our own for the first time and we felt secure."