Young looking

Today got a supplier came to my company. I never met him before and only communicate to him thru phone. So when I went to the company lobby to meet him, he looked at me with big eyes and asked:"You are a Dr?". I said:"Yes. Why?". Then, he asked me how old I am. I told him I am 30+. He said:"You look like 23 only!". Then, I joked with him that I have to buy something from him liao. Haha!! Any way, he said he is serious and not to make me happy so I buy things from him. Hoho.. So must take care some more.