Alba an haife shi ne a Pomona, California, zuwa Catherine Louisa (née Jensen) da Mark David Alba. Mahaifiyarta tana da Danish, Welsh, Jamus, Ingilishi, da Faransanci, yayin da kakanninta na mahaifinta, waɗanda aka haife su a California, duka 'ya'yan baƙi ne na Mexico. Tana da ƙaramin ɗan'uwa, Joshua. Dan uwanta na uku, da zarar an cire shi, marubuci ne Gustavo Arellano. Aikin mahaifinta na Air Force ya ɗauki iyalin zuwa Biloxi, Mississippi, da Del Rio, Texas, kafin su koma Claremont, California, lokacin da ta ke da shekaru tara. Alba ya bayyana iyalinta a matsayin "dangi mai ra'ayin mazan jiya <unk> dangi na gargajiya, Katolika, Latin Amurka" kuma a matsayin mai sassaucin ra'ayi; ta bayyana kanta a matsayin "masanin mata" tun yana da shekaru biyar.
sau hudu zuwa biyar a shekara