The Washington Ballet stepped out smartly into its spring concert series at Lisner Auditorium yesterday with a program made all the more attractive by a new ballet by resident choreographer Choo San Goh, and an acquisition From George Balanchine, the perennially effective "Serenade."

The youthful troupe, situated in that middle domain between appreticeship and professionalism, occupies a singular niche in the current local scene. The dancers are mostly students and graduate of Mary Day's School of the Washington Ballet. The company is intended both as a show-case for advancing talent, and as a proving ground for choreography. Yesterday's performances suggest that his mission is being carried forward with a fine sense of enterprise.

Choo's new piece, "Life in Dance," is in six sections which call not only for a sizable contingent of dancers, including some children, but also readings from poetry by Sassoon, Shakespeare, Hopkins, Tagore and Eliot, and musical excerpts by Vivaldi, Scarlatti, Pachelbel (the ubiquitious Canon in D, which ought to be laid to rest for a while), and Bartok! The sections have headings like "Age and Youth," "Hope," and "Transfiguration."

There's a beguiling innocence about the philosophical ambitiousness of the opu (Choos is 29). The amazing thing is that the result seems neither cloying nor pretentious, and has a number of genuinely compelling passages. It doesn't quite make it as a unified entity> however, and it as a unified entity, however, and too frequently, the dance element is reduced to a glorified sign language! The most impresive portions are precisely those least dependent on words, especially "Hope," a sort of mine panorama about the life cycle, through whi ch the dancers wander like rovindreams.

The performance of "Serenade," which Balanchine choregraphed for his own students in 1934, made up what it lacked in precision with its fresh lyrical ordor. Also on the program was Choo San Goh's perky "Introducing . . .," further evidence of his considerable gift for dance invention.