Work Schedule

I may have an opportunity to transfer to a different department and work the night shift of 3-11. This would enable me to attend classes during the day. It might make my schedule a little easier. I know it will be an adjustment. But I might like it. The problem is I have only been at my job for 7 months. Customarily, you need to be employed for at least a year in order to transfer to another Dept. But I had a meeting with the director of the Dept I may work in and she said she can work it out because she really wants me.
Decisions, decisions.
A part of me feels guilty. I hate to just leave someone hanging. But shouldn't I be more concerned with myself?
I need to think about this over the weekend and come to a decision by Monday. If I decide to go for it. I will have to speak to my director on Monday. I'm very nervous about it because if she decides to block it. She is in the right to do so. And if she does block my move, I worry that it will cause tention in the department and they may look at me like a traitor.
Any advice would be appreciated >>>>>>>What should I do? haha