When Horn began his racing career in earnest at a California race track called Legion Ascot Speedway he found he had much to learn as he was usually the slowest driver on the track. Eventually a few of the drivers gave him pointers on how to pick up his lap times which started to help develop his driving style. He suffered a serious racing accident which broke his foot and burned his back and kept him on the mend for several weeks. At the urging of his parents he promised to abandon the sport. He fully intended to abide by his parents wishes but after three years he began racing again.