Kemco.jp describes Shan as a lively and cheerful “boy” with a beakle craftsman for a father. We correlated this information along with the appearance of Shan, giving us a conclusion that Shan may be a young teenager, probably somewhere around the age of 15. Note that the appearance estimate is highly speculative because of Shan’s chibi artstyle, but all in all, he should still be a boy and shall fall under the age of 18.
Regarding Shan’s height, we have a speculative estimate of 5 feet and 5 inches. This estimate was done by visualizing Shan relative to his sword height at his character profile picture on Kemco.jp (very speculative estimate).