Great subject but this does not only happen to young girls but nearly every woman and men as well (the scamming I wrote about it).
I doubt people will go to a dating site if not necessary. Most do not want a date. Cybersex is fine too.
If it comes to your chat ... I think I would respond like her (alarmed, who knows even in defence, what does he want from he) as well. It also has to do with the way you fire your questions. They simply does not make sense in a normal chat . It would have been different as you would have said: you sound sooo young, like a teenagers, so I wonder how old you are.

I hope some of the "hunters" will read your post and learn something ( let's hope not: how to get what I want by fooling the stupid chicks in a smarter way as I used to behave ..). I will spread your word