Unfortunately no, it is not allowed.

We are very strict about applying the rule that states “The contest is not open to native English speakers. Nor is it open to bilingual students. It is reserved for students whose knowledge of English has been acquired essentially within the regular school system of the respective country. Native English speaking students who have been registered by mistake will be excluded from regional and national rankings and will not be able to win any of the prizes intended for regional or national winners.”

The contest was created to motivate students who don't speak English as a language of their own.