152.4 cm (
) actually very average height for japenese male of that age. Estimation will result in Irish being 165-170 cm at the age of 20 when he strop growing (well, Irish is not normal).
If we consider all the 15-17 year old cast of the cast are normal height as opposed to anime/manga depiction (that depict Houki as huge schoolgirl... which isn't true, Ichika remarked Houki as above average height), he's actually
taller than both Laura and Rin, and about the same height as Maya and Charlotte, just short of Cecilia and Houki.
Also, I'm surprised Lyon's testosterone and adrenaline not firing up, considering the sheer of a dick that other boy is.