I feel what your going thru. I was in the same situation with all the school situation your talking about. I was a senior in high school when i got engaged. Still currently engaged..its been two years now mashallah and getting married soon inshAllah. I had always planned on going to med school to be a pediatrician and at first, I had two other back up plans just in case that didnt work. My parents and I both spoke to my in-laws. And they agreed upon letting me complete my education even though i have so much of it left. Inshallah ill be able to finish !
Moreover, your issue about the relationship, well if im not mistakening, Islam says somethign like if its going to ruin your relationship with your husband or soon to be fiance. Dont say anything. Here is a link that might help: Islam QA - Effect of a wife telling her husband about her bad past, and the effect of that on her life good luck. May Allah ease all your worries. i`A