Washington's Great Youth Experiment starts today against the Dallas Cowboys, once again a legitimate Super Bowl contender. If they had their choice, the Redskins would have preferred to start their maturing process with a less formidable opponent.

Coach Joe Gibbs says he wishes he could have two more weeks to prepare his team. And some players admit that facing the Cowboys a month from now would have been a lot more palatable.

But the Redskins can't postpone this 1 p.m. game with America's Team in Team in RFK Stadium (WDMV-TV-9). Nor can Gibbs or his players realistically predict what kind of outfit will confront the talented Cowboys throughout this late-summer afternoon.

In his debut as an NFL head coach, Gibbs brings from San Diego a reputation as an offensive innovator. His players believe he is clever enough to confuse and frustrate the Cowboy defense, producing points from a unit that is hardly settled, much less ready to roll over the Doomsday boys.

This faith in Gibbs has kept the Redskins optimistic this week when confronted with some seemingly insurmountable odds that makes the current Las Vegas line (the Cowboys are favored by 2 1/2 points) appear much too short. Consider.

Washington's offensive line features four players making their first NFL starts, including two rookies (tackle Mark May and guard Russ Grimm) who were worried about winning the national college championship just eight months ago. The Cowboy front four, the best in the NFL, probably can't wait for the game to start.

The Redskins rushing defense, which the club tried to strengthen with offseason moves for Fred Cook and Wilbur Young, still features all the same major figures from last season, when Washington was 27th in the league against the run. And now the Redskin have to halt Tony Dorsett, who never has had much success against Washington but is coming off the most impressive preseason of his career.

Dallas has made limited personnel moves in a year, with only its secondary remaining unsettled.In contrast, the Redskins will have eight new offensive starters and 22 new players in all from the team that opened the season last Septekber against the Cowboys, a 17-3 Redskisn loss.

"I honestly don't know what to expect," said Gibbs. "I'm as anxious as anyone to get this game started. I've been going through the same emotions, the same paranoia, the same fears as any new coach would in this situation. There's pressure and there is anxiety.

"We've made so many changes and so many things are new, starting with the staff, that only a fool would make a prediction at this point."

Still, the Redskins are not all that helpless. "They have the running backs that they lacked last year," says Cowboy Coach Tom Landry, who remembers how much easier it was to defense a Washington team that lacked John Riggins, Joe Washington, Terry Metcalf and a rejuvenated Wilbur Jackson. Lasts year, the Redskins were 23rd in total offense and 25th in points.

Gibbs preaches aggressiveness and unpredictabilty on offense. The Redskins won't shy away from passing, even in the toughest situations, although their receivers -- Art Monk, Ricky Thompson and newcomer Virgil Seay (who didn't catch a pass in preseason) -- hardly equal Dallas' trio of Butch Johnson, Drew Pearson and the hobbled Tony Hill.

So much of what Washington wants to do depends on the performance of quarterback Joe Theismann, whose fine preseason showing was marred by contract problems with the club.

"We're all still in a learning process, but I'm as excited as I can be about this team," said Theismann, who will be working on a Dallas secondary that has a rookie free safety, Mike Downs, and two inexperienced cornerbacks, Steven Wilson and Dennis Thurman.

"People are going to be surprised by how we play. I see a lot of reasons to be optimistic. The defense is solid and our line is much more mature than its age would indicate. I've always dreamed of playing for an offensive-minded coach, and I don't want to blow the opportunity."

Injuries have hurt the Washington defense, although cornerback Lemar Parrish was moving better on his sore leg yesterday and is a likely starter. The Redskin secondary intercepted five Danny White passes in one game last year, but, if Dorsett runs unchecked, White will be able to limit his aerial attempts.

That Dallas ground game has been improved by the addtion of Ron Springs at fullback. He may not be a better blocker than Robert Newhouse, but he's quicker and he's a more dangerous receiver coming out of the backfield.

"I think we are moving in the right direction," said Landry. "Danny White has come on strong the past two weeks. But we've got to get rid of the penalties the sack, everything that is bothering us."

The Redskins know all about those problems. They were penalized for 1,008 yards last year and committed 36 turnovers. And to make Gibbs' summer a bit longer, they kept committing similar errors this preason.

The Cowboys have won six of the last eight meetings with their long-time rival. But Pearson says RFK still remains "a hell hole . . . Playing in Texas Stadium is like playing in paradise compared to RFK. The fans there are a lot more hostile, a lot more rowdy. They just hate the Dallas Cowboys."