Hello,
Are you trying to or think about going back to school in real life?

If not, I wonder if there is still some spirited training or education that is needed in your life? I’ve had many classroom dreams before and have had them when God was trying to teach me something or take me thru a training of some kind. You said you were in high school. That’s intermediate level. You’re not at the beginning (primary) but you’re not yet ready for advanced level (graduating high school and going to college). Pray to God and ask Him what he is trying to show you/lesson He is trying to teach. Blessings