I am certainly no expert and have had my ball python for a year now. He/she is about 10years also. This is how I got my snake to eat ft, after a four month fast too. After several attempts on regular feeding days of live rat being refused. I decided to offer live adult mice, still a no go, he just wasnt interested. Since the mice are smaller and less threatening I felt better about leaving it the tank longer, supervised of course. One time the mouse and snake were actually snuggled up together, I was getting pretty frustrated at this point. One day he we dropped the live mouse in, he ignored it for about half hour, then I think he got fed up with it making itself at home in his hide, so he ate it. At last he was eating again, so after all this hassle I decided thats it, frozen. After a couple of successful feeds with a live mouse, I tricked him and gave 1 live mouse as a starter, followed by a small ft rat. SUCCESS!! Did this for a couple more feeds, then tried ft only and we have been completely ft ever since.
Good luck with yours.