Nancy Kissinger can't wait to get into shorter skirts. "The longer you are, the better short skirts look," she said.

Susan Brinkley said, "My knees will never see the light of day again."

Both women were in the front row of the Bill Blass showing of his spring designs at the Pierre Hotel yesterday morning, where a lot of skirts, but not all, cut off above the knee. The shortest were like little baby dresses in black and white with smocking. Others brushing the top of the knee included tailored suit skirts with a narrow ruffle at the hem, and pleated skirts worn under tunics.

Yesterday morning Blass was doing even more shortening on several of the dresses he had pronounced "too dowdy" at his dress rehearsal. Admitting that the skirts were the shortest they have been since the 1960s, Blass said, "In spring the short length gives the clothes an up and makes them seem lighter."

He doesn't expect the women who wore his short skirts 20 years ago will wear them again. In fact, he hopes they won't.

So for them he had some longer lengths, for both daytime and evening, and lots of pants -- including pedal pushers, knee-length bloomers and Bermuda shorts as well as more standard cuts.

"Not Bermuda shorts! I wore them in college, I can't stand the sight of them," laughed Nancy Kissinger. Again, Susan Brinkley disagreed. She thought they might be fun to wear again.

Like Blass, other designers are placing their bets on seveal lengths this season. And so far, no major designer has gone totally mini-happy. At Anne Klein, designers Donna Karan and Louis Dell'Olio are cutting their skirts in four lengths, from very short skirts and culottes to a sailor skirt that cuts off below skirts so far, with beaded or knit chemises hiked up with a belt. (Unbelted, they end much closer to the knee.) And he shows dresses and skirts below the knee as well.

Calvin Klein's silk chemises show up over pants tapered below the knee and can be worn as easily with longer pants or without pants at all. His short sweatshirt dresses are meant for weekends.

Designers in both Europe and New York started to hike up hemlines several seasons back. Full-blown, overscaled sesigns of the rumpled and layered look were cleaned up to neater, trimmer styles. And as proportions got narrower, shorter skirts became part of the look. This season they are shortest yet. But they are still a far cry from the uniform mini that was around more than a decade back.

Henri Bendel president Geraldine Stutz says we will never see the miniskirt as a major fashion again. "The mini was the last fashion imposition on women," says Stutz. "If you look at any old pictures and see women in minis . . . on anyone over 12 they look terrible.Women are not going to let that happen again."

But in the end, most designers are leaving the final choice up to the customer. As Bill Blass says, by the time these things arrive in Washington stores, they will be several inches longer.