Why does keevan think he might be kept from impressionsmallest dragon boy?

Keevan believes he might be kept from impressing the dragon in "The Smallest Dragon Boy" due to his small stature and perceived lack of strength compared to other candidates. He fears that the dragon might choose a larger, more capable boy, leaving him without a chance to bond with a dragon. Despite his determination and desire to impress, he struggles with self-doubt and societal expectations surrounding the dragon-rider selection process.