As a child, his facial structure stayed the same, just becoming sharper and more. Sae is noted to be the only person who can control shidou, and calls him ‘his little demon’ Boys, on average, start getting the first, barest hints of stubble on their cheeks by 13
Oliver Aiku Wallpapers - Wallpaper Cave
I was 14 when i shaved for the first time after it formed a carpet under my chin
And a 19 year old adolescent can very well be nearing his maximum height, and aiku is tall.
Oliver aiku is a cheating bastard, but his wife is willing to forgive him every time