I got really confused wondering why the button wasn't there but when I navigated to my albums through my classroom > albums I was able to get the button. The place on the site where you can view your albums and add a new one, and the place on your profile where you cannot, they look very similar, so it communicated that were the same kind of "thing" in the system and my brain expected the same functionality, hence the confusion. My suggestion is either make these two ways of viewing an album look different or make it so there is an "add album" button with viewing your own albums on your own profile.