The Reagans had 1,000 friends in for their first White House party last night, and like a football lteam at a victorious homecoming dance, the mood was : We made it.

"This morning I got up and went to the Oval Office -- and went to work," said a laughing President Reagan of his first day on the job.

"Oh, my God, we're all about 10 feet off the ground," said Mike Deaver, who'd been sworn in just hours earlier as deputy chief of staff.

"I was thrilled with the gala," said Frank Sinatra, "contrary to what the critics thought. If critics weren't critics, they'd be snipers. You like that quote? I got a barrel of them."

Sinatra was one of dozens of Hollywood stars interspersed among the politicians and Inaugural Committee staff as they wandered wide-eyed through the historic state rooms. Many of them, like Johnny Carson, hadn't been there for a while. "A little paint, and this place would look swell," said Carson, who was talking to Jimmy Stewart in the Red Room.

Stewart, who said that Reagan would make a "wonderful" president, said he never went inot politics himself because "1i can't talk fast enough to be a politician."

Although the Carters always entertained plenty of movie stars, they weren't as chummy with them as the Reagans are. Stars in the Carter orbit tended to come for institutional occasions, like official entertainment after the state dinners or en masse for the annual Kennedy Center honors.

The Reagans are "going to introduce a lot of entertaining luster to the White House, in Hollywood-Beverly Hills fashion," said Ed McMahon, Johnny Carson's sidekick. "Every night out there we have three or four parties, and if we don't go, we might hurt somebody's feelings. Glamor will be the key."

But what of the expense, somebody asked.

"Fortunately," he replied, "Mr. Reagan is a wealthy man. And I suppose whoever comes into the White House puts in some of their own money."

Nonetheless, last night's reception didn't look all that different from the Carter White House. There was orange juice and California champagne, but no hard liquor. There were familiar canapes from the same kitchen. A band played in the same place in the same hall. And it was every bit as noisy and crowded as any large party that the Carters ever gave.

"We were given to understand it was just for the performers," said enterrtainer Anthony Newley, "but it turned out to be a football match."

Still, one guest in a position to compare didn't mind at all. "You never get tired of it," said Charlton Heston, who is a top official of the American Film Institute and so was a periodic guest of the Carters. "I am not blase. I guess if one place is the heart of the country, it should be the White House, shouldn't it?"

The reception was paid for by the Inaugural Committee, according to Shelia Patton, Nancy Reagan's press secretary. But Bob Gray, co-chairman of the Inaugural Committee, expressed a slightly different view.

"The president invited us," said Gray. "I was surprised he was so generous about singling us out."

Whoops. Patton was asked to clarify.

"Peter McCoy" (Nancy Reagan's staff director), she said, "said the Inaugural Committee was paying for it."

"Well," someone observed, "somebody better the Inaugural Committee."

Guests had plenty of time to drink several glasses of blanc de blanc before the reagans came down to the East Room from upstairs. The crowd was eager to see the president the first time in the White House during his first day on the job.

"Well," said Reagan, opening his remarks. Everyone roared, the memory of Rich Little's Reagan impression at the gala fresh in their minds; Little began every sentence with "well . . ." Enlarging on this last night, the president continued: "If you've got a stage wait, that'll fill it as well as anything."

He told of making a batch of telephone calls to world leaders in the morning. One prime minister told him everyone in this country had watched the inauguration. "He said the reaction was, there will never again be one like it," Reagan related. The guests laughed, realizing that the release of the former hostages had takene up so much of the inaugural spotlight.

Nancy Reagan made no remarks but stood by his side, wearing a plum-colored Adlofo silk taffeta skirt with a ruffled blouse in lilght pink. The vice president and his wife, Barbara, were also on the stand.

No receiving line followed Reagan's remarks. But people mobbed them like they were old friends, and in fact, they were.

Said Jerry Zipkin, a New York old friend who'd been at the White House before: "I now have a much, more closer personal relationship with the inmates."