Don’t be startled by the number of teenagers – not even late-teens – who take part in the Viennese frolics of Jean-Pierre Bonnefoux’s “Blue Danube” as N.C. Dance Theatre opens its season. Yes, NCDT’s main company has had an influx of new, young dancers. But they aren’t that young.

Here’s the explanation: To amplify the swaying and swirling of “Blue Danube” – which is set off, as the name suggests, by buoyant Strauss waltzes and polkas – Bonnefoux has drawn in members of the NCDT 2 training company and even some of NCDT’s apprentices. Their youthfulness lends a certain charm, actually, to the opening march: The fresh faces, along with the men’s tunics, make the scene look like it could come from a junior-military-cadets ball.

The group pranced through it cheerfully Thursday night at the first performance. Then, as Bonnefoux served up his Strauss-propelled vignettes, the main troupe moved into the spotlight.

Jamie Dee sparkled as she enjoyed but eluded the advances of three gallant men. Sarah Hayes Watson was even breezier as Gregory DeArmond, one of the new arrivals, and Jordan Leeper competed to show off their athletics for her. Anna Gerberich and Addul Manzano sailed into one another’s arms in a scene that climaxed with a wedding proposal. For the finale, everyone was in gowns and cutaway coats, waltzing to the “Blue Danube” as the curtain fell.

If the evening had been a symphony, Sasha Janes’ “Shelter” would’ve been the lyrical central movement. The printed program included this epigram: “Within the shelter of each other we fully live.” The person seeking the support in Janes’ world was Dee – onstage for the entire 20-some minutes, performing with eloquence, tenderness and quiet power at the center of six other dancers.

The revelers in “Blue Danube” were always bubbling aloft, but Janes’ dancers began by lifting themselves out of crouches. Even when they stood, they didn’t personify power – Instead, they kept reaching, twisting, dipping, as if they were searching for strength and security. Men and women alike wore skirts, maybe to give them a kinship, but the men’s bare chests ensured that the genders were never blurred.

The highlights were two compelling pas de deux. In the first, Dee and Pete Walker found each other, bonded but parted. In the second, DeArmond burst into Dee’s presence. Then, after some brusqueness, they managed to join hands and share smiles. With his energy turning to tenderness, DeArmond may have gotten the choicest introduction of any of the new dancers.

But the other newcomers held their own amid NCDT’s veterans – for lack of a more youthful-sounding word – in Dwight Rhoden’s “The Groove.” Dynamic 1980s house music, with its booming beats and live-life-to-the-fullest words, propelled Rhoden’s slinky, fluid and bounding choreography. Often it was athletic, occasionally it was playful, and the men and women engaged in a few confrontational dance-offs.

Pete Walker set it all into motion by flexing his back, and he followed that up with a string of explosive solos as things unfolded. The other dancers also plunged into it fearlessly, and with a few bursts of shake-your-booty flashiness. At the climax of all the exertions, the members of each couple leaned forward, ready to kiss – then the curtain fell.