I started a 4-month internship in January and wanted some opinions on declining an extension. Back in November when I interviewed, my manager mentioned that they were wanting to hire for 8-months, even though the job posting said 4. At the time, I said that I think 8-months would be alright, but hadn't really thought too much about it. When I got the offer, they only offered 4-months and said that they may extend to 8-months depending on the project they were working on. I accepted the 4-month contract. They haven't offered to extend yet, but since that is a possibility, I wanted advice on how to go about declining if they do.
Although I enjoy working here, I wanted to take summer classes at my university, and since I have been gone from school for almost a year (I had another internship prior to this one), have begun missing my classes.
My concern is how to go about declining without burning bridges? I know they haven't offered yet, so this all might be premature, but I feel somewhat obligated to accept since I did mention during the job interview that an 8-month position would be something I could potentially do, and I fear they hired me with the assumption that I'd be ok with extending to 8-months.