Complex sentence: De Mars was born on the Scott Air Force Base and raised in the small community of Alton, Illinois, where she began her judo career at the age of 12 at a local YMCA.
Split into simpler sentences: De Mars was born on the Scott Air Force Base in Illinois. She grew up in the small community of Alton, Illinois and began her judo career at the age of 12 at a local YMCA.