It is okay for you to ask these questions. The more you know, the better.
I am currently enrolled in the Graphic and Digital Design Certificate program where I chose to not take the classes for credit; so I am unsure about the associate degree/undergraduate degree experience. I already did my undergraduate studies at Manhattanville College, where I got a BFA in Studio Art with a concentration in Graphic Design and Digital Art. People ask why I am studying Graphic Design again and I tell them that I am doing it to stay on top when designing, and to fill in anything that I might have missed as an undergrad.
I highly recommend Parsons if you are interested in Graphic/Communication Design. The classes thoroughly go over what is needed to understand the subject that is being focused on. For instance, in typography 1, you get to learn about how and why typefaces were constructed and how to define them. You also get to learn about proper usage. You can learn a lot within a short period of time with these classes. Since I am in the certificate program, without taking the classes for credit, G.P.A is not something that is taken into consideration. A student can take the certificate program for credit. You just pay for the classes that you want and make sure that you complete the 8 course curriculum within 2 years.
So far, based on the classes that I have taken, I really like the school and if I had to do my undergraduate studies twice, I would definitely get a BFA in Communications Design or Product Design. If you need any other tips and links. I will try my best to provide them