Hi there! We're sure your production was phenomenal, and we understand the desire to share your hard work! Uploading to a public platform like YouTube can invite a whole host of legal rights issues, and we definitely do not recommend or condone doing so. It may be worth waiting for our upcoming streaming service, expected to launch next month: https://www.mtishows.com/news/mti-to-launch-new-streaming-service-with-showtix4u-and-bmd.
While the list of available titles has yet to be announced, if Mary Poppins is available, your high school will be able to safely (and legally) share your incredible work!