There is a theme in the movie and I'm not talking about the growing up part. I'm talking about the part where the lead character has to make decisions. Which he is unable too. You could argue, that is part of growing up, but it's just a theme that runs through many people and will touch a nerve.
Of course the one thing our lead character wants, he doesn't get. There is always an obstacle, something that will not let him get it. For some that might feel symbolic (and the resolution this has or hasn't at the end of the movie might feel that way too), but that depends on how you view things. And that is something that has been done clever by the filmmaker here. Shooting in black and white is an art choice, but I feel it works for the general feeling of the movie