for 19 Girls and Me by Darcy Pattison and Steven Salerno
John Hercules Po's kindergarten class is made up of 19 girls... and him. His older brother warns him not to let all those girls turn him into a sissy, but as John Hercules Po discovers, he needn't worry. As he and the girls let their imaginations run wild during recess, they end up digging all the way to The Great Wall of China, floating on the Amazon river, singing to the Man on the Moon, and racing a car 600 miles per hour.
So... 19 girls and 1 lone boy? Nope, even better-20 good friends.
Publisher description retrieved from Google Books.