Legally the only distinction is set by the AoC in your jurisdiction; this ranges from 14 to 18 in different parts of the USA and Europe. And ultimately the issues are exactly the same - the cynical 20 yo gay guy who's cruising for a one night stand with a 17yo is probably far more unhelpful for you than a 40 yo who'd appreciate you as a YF with or without a sexual component to the friendship.