The viola is an interesting instrument, occupying the range between the violin and the cello. Viola parts in ensembles most often serve to fill in the texture of an ensemble, providing unobtrusive additional beauty. The viola was the favorite instrument to play of many famous composers, including Mozart, Haydn, and Dvorak.
Young string students sometimes start on viola. Very often a young string player will take Suzuki violin lessons at first, only switching over to the larger sized cousin the viola at a later point. Either path is perfectly great.