While most are developed by 15, we have a benchmark which guarantees all people are developed. It might be different if a 16 year old and a 15 year old, who is a month away from being 16 or is in the same school year, but it's a benchmark we all have to respect.
I get more annoyed when people refer to paedophiles as paedos. Makes no sense, because that means a paedophile is someone who is sexualy attracted to paedophiles. Makes no sense.