A year ago these earnest ambitious young people were managing store-fronts and phone banks in suburbia for Jimmy Carter. Today they are Washingtonians carefully planning their way to the top in polities, media and government.

Saturday night, at the old K Street boathouse along the murky Potomac, the Young Democrats threw a party for these well-mannered, serious young men and women. Some Carter luminaries, including the President's 26-year-old son Chip and Presidential Press Secretary Jody Powell, showed up, giving the partygoers something to tell the folks back home about.

About 100 people sloshed through puddles of beer and danced to the mild soul sounds of Washington's Johnny Barnes Red Blood during the evening. It was a relaxed, if not sleepy, affair - about the liveliest happenings being an occasional burst of loud laughter as well as an occasional whiff of marijuana being smoked in the darkened corners of the boathouse veranda.

But most in attendance were far too level-headed for such indiscretions. Gayle Rosenberg, a well-dressed 18-year-old Florida college student, talked with good natured determination about her path to the top.

A Young Democrat since age 16, Rosenberg described herself as "straight" and "idealistic," a person who believes in that old cliche, "working in the system." Her plans right now include the proper Washingtion internships, a newspaper career and, eventually, appointment as the nation's first woman presidential press secretary.

"I find politics terribly exciting," Rosemberg said, brushing back her long, black Farrah Fawcett-style hair. "What I really want to do is become presidential press secretary. We can have a woman doing that before we can have a woman President."

Such dreams shimmered in the reality of the likes of Jody Powell, the real and definitely male presidential press spokeman. He, and the other Carter luminaries, were probably the most relaxed people at the party.

Powell, dressed in a blue sports shirt, seemed a little homesick for the campaign trail as he looked over the assembled throng of 20-year-olds. "I guess I've sort of lost contact with these people," Powell, 33, said. "It makes me feel a little old here."

Powell mingled with his long lost friends and walked over to one former Carter warrior who looked particularly nervous and forlorn. "Go get a beer," the presidential aide advised. "It'll feel a whole lot better."

Besides Chip Carter the other notables swigging the somewhat flat beer were public relations man Gerald Rafshoon, presidential personnel director Jim King, media adviser Barry Jagoda and assorted Georgians.Old boy pleasantries, not international politics, seemed the order of the day.

Things were so relaxed Saturday night that no one even bothered to check the floor passes of the people coming into the party. Instead the entry way was flanked by several large men having a good old time drinking beer and flirting with the numerous young ladies in summer dresses. It was even rumored that a Secret Service man was seen wandering around, tieless, with a faint smile on his face.