What symphony did Mozaert write when he was 14?

At the age of 14, Mozart composed his Symphony No. 1 in E flat major, K. 16. This early work, written in 1764, showcases his emerging talent and reflects the classical style of the time. It consists of three movements and is notable for its melodic charm and orchestral clarity. This symphony marks the beginning of Mozart's prolific output in orchestral music.