General literature suggests that the older a child starts school the more mature and therefore the more likely they are to perform better than their younger peers. This suggests that entry age plays a significant role in influencing learning. Even if they are not smarter, older students receive special attention based on their perceived maturity. As a result they become more able. It is a self-fulfilling prophecy. In Botswana, however, the trend is reversed. Older students have been found to do worse. It is hypothesized that this is a result of massive age distribution, where, an 11-year old and an 18 year-old are often in the same sixth grade class, and where older entry students come from lower-income or less educated families. It is likely that teachers, peers and students themselves internalize a negative stigma towards age. This leads to a self-fulfilling prophecy downward. The results of this study indicate that age has a significant negative effect on performance, even when controlling for socioeconomic status, school type and grade repetition. This trend is further observed when comparing students born just a few days apart, who share similar characteristics, but where those born after the school entry date enroll a year late and are therefore older. In the 2000 SACMEQ, students who were 1 year older perform .38s worse on reading and .27s worse on math. In 2006, the results were even more dramatic. Students who were 1 year older performed .63s worse on reading and .34s worse on math. These results are robust to a policy shift, which decreased the entry age from 6 years to 5.5 years, affecting students taking the 2006 but not the 2000 SACMEQ. It is therefore concluded that in Botswana older primary school entrants are at a disadvantage, regardless of their potential. This is a result of age distribution and stigma towards age.