Cecilia "Ceci" Mendoza is Gloria's oldest child and daughter. It is unknown who her father is. She is half-sister to Benny and Julio, and either half-sister or full sister to Elena.
Ceci appears around 7-10 years old when Gloria leaves for New York, and around 3-5 years older than her sister Elena. Ceci did not want Gloria to leave, but Gloria told her she had to go make money so Ceci and Elena could go to a good school and live in a nice apartment. Gloria is gone for many years, and when she finally calls her parents to fly Ceci and Elena over, she has a toddler son, Julio, and is pregnant with another boy, Benjamin “Benny”. Cecilia is an older teenager by this time, looking around 15. This suggest the age gap between Cecilia and her half-brothers is around 13 and 15 years.
This causes a small problem in the timeline of the show and Gloria's life. She is around 41 years old when the show begins (it is noted when she enters menopause in Season 6 that she is quite young for it). Benny is around 15. If Gloria was 26 when she had Benny, and Ceci was 13, Gloria would have had to give birth to Ceci when she herself was 13 years old.
Because Gloria stays away from her daughters in Puerto Rico for a long time, apparently not staying in maternal close contact with them, her relationship with her daughters break down. Ceci tells her she does not want to come to America to live with her. When Gloria says "I am your mother", Ceci simply replies "Since when?"
It is implied by the girls' absence through out most the series that they end their relationship with their mother (almost) entirely for a long time..
Celia appears last episode seemly having forgive they mother. As she is seen in a house with Gloria and her brothers as well as what is believe to be her child