IMO, the best way to start is with a larger board, than you ultimately need. With respect to "wakesurfers" your 5'10" is large. I think that most folks find as they become more proficient, they are able to step down in length.
The shorter boards and wakesurf specific boards offer a number of advantages. One, is that radical moves are possible. Similar to shortboards in the ocean. This picture of James shows a quick cutback. Even if you have the skill to flip your 5'10" 180 degrees, the length makes it unweildly for even the simplest of moves.
I think it's human nature to want to progress your riding. The wakesurf specific boards will help you in that regard.
However, if your intent, when wakesurfing is just to cruise, never really attempting more than staying in the pocket, your current choice is fine.