Hypothetical situation regarding a FT offer

Hi,

So this is a hypothetical situation (unless any of you here have experienced something like this, then please respond to this and let me know your stories or thoughts). Lets assume I'm in my junior summer and I've finished my SA internship, I recieve a FT offer from the firm (doesn't have to be IB but it works best in this situation). However I know that I will not have the required amount of credits to graduate at the end of my senior year and will most likely need to complete an additional semester to do so. What happens then? Is it possible to arrange a later start to the FT offer? Or possibly accept the FT offer but somehow negotiate to start the job with the next incoming FT class? Please let me know your thoughts on this and if anyone has been in a situation like this please respond to this post. For those in the industry already, how would you go about hiring someone like this (would you even extend a FT offer)?

Thanks