Starting with Special 20 C

Hi David, Yesterday I purchased my first harmonica - the Special 20, C (as advised by the store owner). But as your lessons appear to be around the use of an A harmonica, do I need to buy an A harmonica or will I still be ok using the C? I thought this might be a common problem but couldnt find any other similar questions in my search, so apologies if this has been addressed before. Thanks!