An increasing body of studies suggests that bilingual persons are better than monolinguals on a variety of cognitive measures. Thus, the present study investigates the relationship between the onset age of bilingual and the development of cognitive control among Nigerians. 10 bilingual students studying at University Putra Malaysia have been selected to participate in this study. They are divided into two groups: 5 early and 5 late bilinguals. The data are collected using online English proficiency test and E-prime software as instruments. Both groups are examined for English proficiency and performance on a flanker task. The result demonstrates that early bilinguals are more proficient in English than late bilinguals. Moreover, early bilingual performs better than late bilingual on flanker task. Based on these findings, it can be concluded that being early active bilinguals tend to have greater advantages in cognitive control and higher language proficiency.