First off, never talk to your administration with an "Us vs Them" mentality or even think about feeling that way. They definitely have founded concerns.. It doesn't help. As others have suggested, talking to other well established teams with accomplishments under their belts tends to make the administration recognize that this program accomplishes great things. If you can't get another team to help you, print off Chairmen's awards and give them to your principal/school board. Another way is ask for space in public meeting to do a presentation. Bring a robot, bring everyone assosciated with your team, bring a video, bring testimonies, bring
this whitepaper.
Just remember to never take the "Us vs Them" mentality and you should come out all right.