Whoah. No. Way to small. I did a lot of research once about stalling horses, and found a rough estimate for a 12x12 stall for a horse would be about 8x8 feet for the average person. So, that means a exercise area smaller than 8x16. Imagine that plus some controlled exercise a few times a week. I would say the smallest with riding a few times a week would be 25x75. My little run for temporary winter confinement is 25x110.
“Good things come to those who wait… greater things come to those who get off their ass and do anything to make it happen.” - Unknown