I got my F1 reinstatement in one yeas because USCIS lost my application materials and I applied two times. I got it three days before I left US. I couldn't wait any more because you can not work legally with F1 pending.
As for your situation, you can get it if you have good reason to explain you situation.It takes 3-6 months.
The bad thing is that you are finishing your degree and they might think you don't need F1 any more. You can not reinstate F1 just for change of status. Try to study one more semester and you'll be fine.