If your school is a public school then it is in a city or community that includes other schools. Call your district office and ask to speak to a curriculum supervisor for science education. Ask them. It is likely that you can participate through another school in your district. If none of the schools in your district sponsor science fairs, you might try calling adjacent districts. If you attend a private school, your public school might allow you to participate in the science fair at that school. Good luck!