Thranduil glances up from his reading. If it were a young, awkward, bashful statement, he would have laughed merrily. Instead, this guy is acting like he's trying to pinpoint an unusual aroma in a glass of wine he's about to sample.

"To a mortal, perhaps." To an elf, Thranduil is fair-to-middling with regards to age. In other words, he's younger than the sun by 410 years, give or take.