A Woman Leads a Marine Infantry Platoon for First Time Ever About 35 men in the Third Platoon of the 4th Marines' Echo Company take orders from 24-year-old Marina Hierl. First Lt. Hierl is also br the first woman to pass the br Marine Corps Infantry Officer Course. The 13-week program br is both physically br and mentally grueling. Major Brian Block, Marine Corps spokesman, via CNN 15,885 women currently serve in the Marines, about 8.6 percent of all active duty members. Major Brian Block, Marine Corps spokesman, via CNN In the 242 years of the br Marine Corps existence, First Lt.