Then change it... But it might not solve your issue. Nothing says you cannot purchase a new domain name and hosting. However; as esmi has indicated, whether or not your school blocks your site due to domain name, host, content-category, custom administrative settings, or simply by platform (think "wordpress", "joomla", "blogger", etc...) ultimately, it will still be up to your schools IT staff to allow it or deny it access.
Speaking to your school IT dept first, may save you a lot of time and energy (and maybe even some money), if you can convince them that there is a legitimate reason for them to add your site to the list of exceptions that will allow access through your schools site filtering mechanism.