Hi Mia, I dream of school and school related things ALL THE TIME!
Along with pregnancy, it's one of my top three dream themes.I notice for myself, I dream of being back in school when there are situations or times in my life when I am not really challenging myself enough, and I am sort of just sailing along, without any kind of plan or mental stimulation.
That's when the dreams of school pop up, as if to say, LEARN SOMETHING, DO SOMETHING, USE YOUR BRAIN!!!
Not saying that would be necessarily true for you, but that's the way it is for me.
Nevertheless, if you notice themes in your dreams, try and trace back to what was going on in your life when you had similiar dreams, and pretty soon, you will have your own 'dream guidebook'. Which is much better than relying on the ones you can purchase...
anyway, here is an interp..
From 'Your Dreams and What They Mean'
School: The school of life with all its lessons to be learned.
That book doesn't have a listing for graduation.
But, the fact that you graduated FIRST, then when back to school, would seem to me to mean that you have completed one lesson and you are now embarking on new learning.
Best Wishes.