NORCECA Qualification Pool H, at Santiago de los Caballeros, Dominican Republic, she took the public ovation at the Gran Arena del Cibao winning the Best Digger, Best Receiver, Best Libero and MVP awards. She then participated with her Junior National Team she won the silver medal at the 2009 U20 World Championship, being awarded Best Digger, Best Receiver, Best Libero and MVP awards. She won the Best Digger, Best Receiver, Best Libero awards and the bronze medal with her team at the 2009 Final Four Cup held in Lima, Peru. She then played with her Senior National Team, winning the Continental Championship at the 2009 Women's NORCECA Volleyball Championship, and was awarded again, Best Libero, Digger and Receiver. This win qualified her team to the 2009 FIVB Women's World Grand Champions Cup, there she was at the age of 17 one of the youngest players. The Dominican Republic and Castillo won the Bronze Medal of the event. 2010 Castillo crowned her 2009 performance winning the 2010 Dominican Republic "Athlete of the Year" and 2010 Dominican Republic "Volleyball Player of the Year". She started the 2010 year winning the Best Libero, Digger and Receiver awards at the 2010 Pan-American Cup, won by her home team playing in Rosarito and Tijuana. Two weeks after the Pan-Am cup, she won the silver medal and the "Best Libero, Digger and Receiver awards at the 2010 NORCECA Junior Continental Championship U-20. The Dominican Republic Olympic Committee selected Castillo as the Dominican Republic Flag bearer for the 2010 Central American and Caribbean Games held at Mayagüez, Puerto Rico, from July 17, 2010, to August 1, 2010. In the volleyball tournament of the Regional Games, she won with her team the gold medal. She later played in Chiapas, Mexico winning the Best Libero and Best Receiver awards, along with the gold medal with her National Senior Team at the 2010 Final Four Cup. Castillo later participated in her first Senior World Championship in Japan, finishing second in digs and Best Libero categories, and being 17th with her national team. At the end of the 2010 year, Brenda joined the Dominican Republic club Mirador that participated in the 2010 FIVB World Club Championship finishing in 4th place with this club and earning the Best Libero award. 2011 The Puerto Rican team Criollas de Caguas signed Brenda for the 2011 season, as her first international club experience, joining the