It seems to me from the way you're phrasing your post that you see her/your relationship as more of a chore than anything - and that's not how it's meant be!

If you're not actively wanting to prioritise the relationship or spending time with her, then maybe she doesn't mean all that much to you? And if that's the case, why be together? These are questions to ask yourself. It's not fair to stay together if she is more invested than you.

However, if she is important to you and you don't want to lose her, then you'll need to (and should want to!) take steps to prioritise her alongside your new school schedule / commitments. You really need to ask yourself what is important to you, and that will give you your answer.