If you are meeting a photographer, it is a good idea to bring an escort with you. It is a good idea to friend a friend, boyfriend, mother, who ever. Being a model should not involve you doing something you do not want to do, or to be put in an awkward or unprofessional situation. In today's world you do have to watch your back, protect yourself and even those who seem professional really aren't, even people with quality work can be jerks, and those who might promise you things with other objectives in mind, are not worth it.
Whether you are meeting an agency, or photographer, or casting director, if you are not comfortable to go alone don't! Bring a friend. They can wait in the hallway if you want to. But these days there are too many scams out there, and too many terrible unprofessional people out there and alot of scams and bad businesses out there. So be careful, promoting yourself and being involved with the entertainment business is no joke, you will run into some jerks, and you do not have to mingle with them. Choose not to.