Against all odds, the scrappy squad from the Lower East Side’s Seward Park high school campus is headed to the national championships at Walt Disney World next month. They are believed to be only the second Manhattan public high school ever to make the nationals. The 14 girls managed to secure a spot in the Feb. 11 Universal Cheerleaders Association competition despite scant experience, hand-me-down uniforms, a lack of equipment, or dedicated practice space. The team only has three mats and really needs seven, according to Giana Quinterno, the coach who helped get the squad started when she arrived in 2015 as a social-work intern. A former high school cheerleader, Quinterno saw a notice for team tryouts and volunteered to pitch in, soon becoming the volunteer coach. The city’s Public School Athletic League doesn’t recognize cheerleading as a sport and doesn’t fund it. Few city schools even have teams.