At 50 there is going to be ilevel gear requirements; so yes you will need to upgrade your gear in order to access those new dungeons and part of them are main story requirements.

Also if others explain to you about your gear; they are probably not hating on you; in fact they are probably giving you a heads up next time I suppose. The only problem is that they address it in a negative form, (ex. Why don't you have any jewelry?)

Also if you are not sure about anything ASK QUESTIONS!!, ask your FC, ask your friends, ask in link shell, ask your party members that you que'd with. There is nothing wrong with anything in particular that you are totally not sure of to ask. And depending on the person, he/she can help you or answer you. If you are eager to learn something, why not ask right?