Why is our son so stubborn?

'His' future is his. You can't control or change that. I was 28, married and had 2 kids and a new house when I went to and completed college. Altho I enjoyed the subject I did not continue in that area after about 10 yrs I was injured at work by a patient and am disabled. Be happy he's happy. I cannot ride horses (my great love), race cars or a lot of physical activities. So, let him go.