It wouldn't be a bad idea to limit your usage of the camera underwater for your dives, and possibly even leave it on the boat or shore for first one or two dives in the ocean. Reason being, as a brand new diver everything is going to be new (procedures for descending and ascending, buoyancy control, etc) and you'll have to think about it all until it comes natural, like anything. During this time you don't want have too much overload, and having an extra hand free instead of a camera in it makes things way easier, mentally and physically.
Also, depending on the dive shop, they may not even allow for a brand new diver to carry a camera. I can remember only being allowed to do so on my 4th dive of my open water certification. You may be able to ask an instructor or divemaster to carry it and take some photos for you though.
With all that said. Pay attention to your instructors, and the number 1 rule is to never hold your breath...always keep breathing and your airway open.