Killed in the fire were Diedra Martinez, 2, Jimmy Martinez, 4, and their cousin, Nathaniel Ramirez, 3.
Garcia had gone to the mobile home with her children to babysit her nephew, authorities have said. The fire was reported about 8:30 a.m.
Garcia was taken by helicopter ambulance to University Medical Center.
A few hours later, a young boy and his mother died in a house fire in Lubbock. Alisha Loftis, 35, and her son, Gianna Shelby, 3, were rescued from the home but pronounced dead at the medical center.
Both fires remain under investigation, officials said.