So I am 15 almost 16 and have about 25 logged hours. I will be soloing in early December. Today we were out in the training grounds of my area practicing stalls. I fly Cessna 150s primarily. I went up to do a power off stall at about 2500ft AGL, I had no rudder inputs and neither did my instructor. Out of the blue we entered a spin and for a solid few seconds all I could see out of the windshield was ground. Fortunately, my instructor has tons of hours in military, GA, and commercial (pretty sure close to 15,000hr) and he got us out. I have always heard of what to do in a spin (idle, full opposite rudder and push nose down) but it REALLY took me by surprise and I don't know if I could have gotten out without him in the plane. I was very lucky that we got out of it and that we were at altitude. Neither of us could figure out why it so suddenly entered a spin when there was no rudder inputs or anything like that. Anyway, just wanted to tell the story so yup, there you go!