Counting Years - NLD Style

While beginning to test my son 5 year old son for NLD, the neuropsychologist asked him to help her fill in the blanks on the top of the test form. When she asked his age, he said that he's been five for two years now. She look puzzled and surmised that he must have meant two months, but he corrected her. "Actually, I turned 5 in the Year: 2000 and am still five now in 2001. That's two years. But I'll be 6 in the last month of 2001, so I'll be two years in this year also!" 

She had her diagnosis at that point but continued the test anyway.