Definitely. Just enjoy learning to play well with whatever key harp you wish. If you are taking lessons (e.g. from Luke @Luke) then it is typical that most of the instruction assumes you have and play a C harp, but that is only important if you wish to play along and be in the same key as the instructor – all of the techniques taught apply to any key diatonic Richter blues harp.
Regards,
– Slim 