Hello friend,It reminds me of the 4chan meme "an hero". The thing is though, there is actually nothing grammatically incorrect with either "an hero" or "an prostitute". The a/an thing is purely for ease of phonetic pronunciation and has no written hard-set rules on when either sould be used; it's all down to the choice of the speaker.
I thin a good appraoch to find an prostitute via online is to use video chat. This allows you to see the other in real time, with a real face and have a real conversation. If you harmonize in the chat then maybe meeting is a good idea. If not that’s ok too.
If you think "an prostitute via online" is correct, then that's fine, and "If not that’s ok too."