Do you like this prologue? It's super short!?

I would suggest rewriting it as Chemistry, A. History, A. and so on, with a period after each grade instead of a comma. Yes, you should capitalize all subjects because they are proper nouns. Also, I would suggest that you replace the cuss word with a negative phrase such as, "Oh man." or "Oh no." as cursing is the language of the simple and uneducated. I hope this is of help to you.