I don't think it is .5 as it is still spring. But 13 may be correct.
Ill give him 12.90yrs but is just on the verge of his 13th birthday if its a recent spring picture. I think he has broomed his lamb tip and one full year off, approx 4-6" and 2 annuli. You wont see the 13th year ring as it will be right below the hair line.SG