Ephebophilia isn't used to describe the presence of sexual attraction to people ~15 years old, it is used to describe primary or exclusive sexual interest in people ~15 years old. Pretty much everyone has some level of sexual attraction to people ~15 years old (the 'term' for that would be 'average').
Paedophilia is also often misused as a term, because it means attraction to pre-pubescent people, generally younger than 11, but sometimes as old as 13. Not 17, not 15, not even 14.
The laws we've universally passed to for pornography (actors must be 18 or older) to protect vulnerable <18 people from exploitation have bled into the public having an opinion that having sexual attraction for people less than 18 is equivalent to paedophilia, which is pretty strange (I know that I would personally view someone who is attracted to a 15 year old differently than someone who is attracted to a 5 year old). Laws of consent obviously differ a lot per country, but are for the most part 16-18, sometimes as low as 14.
There's even more to it, because our laws regarding age of consent do not exist exclusively to protect against paedophiles: they are in place to protect young people from exploitation. Public opinion is sort of confused about this, again.
If a media outlet says 'Person X accused of sexual relations with a minor', they have not in any way said that person was a paedophile, just that person A had sexual relations with someone considered a minor (as old as 17 in some places). The public often takes this as 'Person X accused of paedophilia', which is incorrect.
There's also the issue of viewing all pornography of people <18 as 'child pornography'. This is basically a legal grey zone, which is silly, because a person who forces a 5 year old to take sexual pictures is pretty different than someone who asks a horny 15 year old for pictures (in my opinion, again).
To go back on topic, Prince Andrew being accused of having sex with a 17 year old has nothing to do with paedophilia (at least not with the legal or psychological definition of paedophilia), it has to do with exploitation of a minor.