What is the allowed time for offering Jumu’ah prayers?

Assalamu Alaykum, I have Jummah prayer in my school alhamdulillah but Dhuhr is at 1pm right now and we do the prayer during lunch at 12:00-12:45 pm. The prayer plus the khutbah takes 30 minutes. If we were to do the Jummah at its proper time, we would miss almost half of the lesson (for reference, a period is 75 minutes). My school had already asked a local Sheikh and he said it would be permissible to pray earlier. My friends are concerned about the source. Would it be permissible to pray Jummah earlier due to our circumstance?