Talia Simonett, a sixth-grader, and fifth-grader Christian Sanderson, both students at St. John’s School in Hopkins, perform the song, “Sixteen Going on Seventeen,” during a rehearsal for the school’s production of “The Sound of Music” March 23. All 70 students in grades three to six are in the musical, which they will perform at the Hopkins Center for the Arts in April. “I think the large venue for our elementary students has been proven to build self-confidence, pride and community, and the tradition of excellence in the fine arts has been passed down to our new young families,” said Peg Pavek, who has been directing the annual musical since 1995, when the Hopkins Center for the Arts opened. This is the fourth school production for fifth-grader Jack Feld, who plays wise-guy Max Detweiler, “I like this one because I get to be with some of my friends and I got a bigger part, so it’s fun going to rehearsals.”