Her first competitive outings came in 2006, when she set a personal best of 1:16:48 hours as runner-up at the Mazatlán half marathon and recorded a time of 2:51:32 hours at the Mexico City Marathon. She improved her best marathon time of 2:43:21 hours the following year and won the silver medal in the 5000 m at the 2007 NACAC Championships in San Salvador. Romero made her debut on the global stage at the 2009 IAAF World Half Marathon Championships and finished in 39th place. The following year she ran a marathon best of 2:42:33 hours in León, Mexico before going on to claim the women's gold medal in the event at the 2010 Central American and Caribbean Games. She ran a half marathon best of 1:14:13 hours at the 2010 IAAF World Half Marathon Championships in Nanning to finish in 22nd place in the women's race.