It's spring, and with the first robins and the first warm days come little league and hundreds of young boys and girls who only want to play the national pastime. The fields at Fort Tilden were crowded last weekend with players of various ages and talents who were playing their first games for the Rockaway Little League. And, while the name of the game is having fun and learning skills, there were lots of winners and few losers. The Pee Wee Seniors are in the second and third grades. The T-Ball toddlers always seem to be having the most fun at the little league complex. The Pee Wee Juniors, mostly kindergarteners, and their coaches make a pitch to learn the game's basic skills.