COMPTON, Calif. — Thirteen-year-old Kokoro Sagae felt very much at home as she took the field with her teammates on Saturday. But she also knew that this game would be different than most she’s played in. Sagae, like the other 100 girls currently participating in the Trailblazer Series in Compton, Calif., has been playing baseball most of her life. Most other times, she’s the only girl on a field full of boys. But not this weekend. The tournament is for girls only — and for many of these young athletes, it’s the first time they’ve ever had this kind of opportunity.