GLENWOOD-Ten-year-old Kristen McCormack began playing piano at the age of four and started lessons with Margaret Korczynski of the Sussex County Music Workshop at the age of five. She will make an appearance at Carnegie Hall in New York City on June 19. Performing at the concert is by invitation, and only the best young piano artists, some from as far away as Costa Rica, appear. When Kristen gave a solo performance for Dr. Anna Maria Bottazzi, she was encouraged to send an audition tape to the music jury sponsoring the concert. Dr. Bottazzi, of the Pinault School in New York City, has performed for the Pope, at the White House, and at Carnegie Hall. Kristen, who is in the fourth grade at Rolling Hills Primary School, was just evaluated by the National Piano Guild and received a score of 29 out of 30, playing 4 pieces from the senior level (high-school age). She has performed for the National Piano Guild the past five years and has achieved gold-status proficiency. Last month she competed at the Sussex County Piano Competition and placed first for the third year in a row. This year she moved up to a more competitive age group and took the first prize. She will be performing at the Sussex County Winners Concert on June 12 and the New Jersey State Fair in August. In addition to piano, Kristen finds time to be on a soccer team and is a registered junior handler with the American Kennel Club, showing German Shorthaired Pointers in the ring.