Blumenherst was born in Scottsdale, Arizona, and began playing golf at the age of four. She attended high school at Xavier Prep in Phoenix, where she was a four time Rolex All-American and was the third ranked national recruit as a senior. She led Xavier Prep to the 5A state championships for four straight years. She holds Arizona's 5A High School Girl's Golf State Tournament record with a score of 69-66=135 (-9). After graduating in 2005, she chose Duke over perennial Pac-10 powerhouses.

Blumenherst was named the National Freshman of the Year by numerous publications. She had the lowest stroke average by a Duke freshman, 71.62. She became the second freshman golfer at Duke to win her first collegiate tournament. She set a Duke freshman record with a 54-hole total of 208 at the Mason Rudolph Championship.

She was named the NGCA National Player of the Year for the second year in a row. She won the Golfstat Cup joining only LPGA great Lorena Ochoa as the only two-time winners. She set a school-record 71.00 stroke average. She tied an NCAA record with a nine-under-par, 63, at the NCAA East Regionals.