This study stems from the debate over bilingual advantages in cognitive control. Two experiments were conducted with young adult non-immigrant bilinguals, in order to explore the effect of the age of second language immersion. Participants were given a colour-word Stroop task to assess linguistic cognitive control, and an Attention Network Test to examine non-linguistic cognitive control. Findings revealed important differences between Simultaneous and Early Sequential bilinguals in the Stroop task, although these occurred when both languages were mixed. Furthermore, simultaneous bilinguals showed an increased Executive Control, suggesting enhancement in attentional skills. The experiment showed that task effects were influenced by the language environment.