Comment: People have totally inaccurate concepts about 15 year old girls. Many are Not innocent flowers.
A 15 year old girl can wrap a 30 year old man around her finger. Wake up people! In this case, she  exchanged nude photos with the young man first . These girls know exactly what they are doing...until their little escapade is exposed, THEN they don't Know what they were doing! ah huh. Riiight. 
I know of what I speak, for as a young man of 19 myself, (many moons ago) I was constantly tempted by girls as young as 12! One 14 year old was extremely aggressive and did not let up until she got what she wanted- when she was 21. Most parents (and yes, I am a parent of a 21 year old daughter) are in complete denial that their little sweetness could possibly want to have, and enjoys sex! I once (when I was 31 !) was  approached by a girl who I believed to be older (at Least 18). She gave me her #. I dropped the whole thing when I discovered she was 16. 
Most parents deny these incidents occur.