Can I switch to clear braces after I just got metal? (photos)

A lot of orthodontists do that; clear on top and metal on the bottom.  The reason is that the porcelain (clear) braces can cause a lot of wear to the opposing teeth and the metal brackets are smaller so easier to manage in this way.  Unless you have a deep bite, which I can't tell, you could switch, but not likely right on the spot, it is a time consuming appointment to do so (at least an hour).  You will also likely incur an additional fee.  NYU doesn't do a lot of Invisalign (I taught there for nearly 20 years) but you're a really good Invis case, you might consider.  Best of luck to you.