Upton was born in St. Joseph, Michigan and raised in Melbourne, Florida. She has three siblings. Her uncle is Fred Upton, the US Representative for Michigan's 6th congressional district. An avid horseback rider, she showed for the American Paint Horse Association and competed on a national level. With her horse Roanie Pony, she won three APHA Reserve World Championships, in 13 and Under Western Riding, 13 and Under Horsemanship and 14–18 Western Riding and named the 13 and Under Reserve All-Around Champion at the APHA World Championship Show, giving her a total of five championships. In addition, Upton ended up third overall on the APHA youth Top Twenty. With a second horse, Zipped, she won 14–18 Western Riding and was top 5 in 14–18 Horsemanship and 14–18 Western Pleasure in 2009.