Kammala jumla mai zuwa: An haife shi a Kingston, Rhode Island, Amurka, Fierro ya kasance mafi kyawun dan wasan chess na Ecuador na shekaru da yawa, kuma ya wakilci Ecuador a cikin gasar Chess Olympiads goma daga 1994 zuwa 2012. A cikin 1998 ta taka leda a ɓangaren buɗewa (tare da 'yan wasa maza da mata), yayin da a cikin sauran bugu ta shiga cikin gasar mata. Sakamakonta mafi kyau shine lokacin da ta ci 9.5/13 a cikin
1996 Chess Olympiad na mata a Yerevan, da 7.5/8 a cikin 2008 Chess Olympiad na mata a Dresden, don lashe lambar azurfa a kan jirgin 1 a lokuta biyu.