If you don't want to see a seventeen year old punter then that's up to you (and I wouldn't either), but I don't understand the pearl clutching or the 'report' (and if this app is full of people blacklisting numbers just because they got a stupid text message then God help future users if it falls down, because literally nobody will ever learn to screen if they need to be told that someone who wants a nice long chat on the phone without any mention of a day/time is a timewasting fantasist).
Anybody who has age restrictions only has to put them on their ad, after all? Mine says my services are for men aged 18+ only and I still get numpties texting asking me to see couples and so on. They're deleted and instantly forgotten.