Intermediate Progression Halt.

Thank you for reading. I've been surfing for one year (intermediate) and been having difficulty with wave count, pop-up foot placement, quality of ride, and progression in general. I am 5'11 135 lbs and extremely fit and surf about 3-4 days a week. Riding a 6'1. On some waves after I pop-up I will realize that my foot placement is off and will either wipe out or ride the wave real awkwardly. This problem began after I put in these new FCS 2 neo glass fins and immediately the next session I was having difficulty.Or the problem may simply reside in my board as it is very thin. However the times that I do hit it I have a lot of fun experimenting with turns and generating speed. I've saved up a bit of money so I am open to a new board or set of fins that may solve my consistency issue. It may seem that I am trying to "run before i can walk" with this board and I believe that with a different board or set of fins I will be able to progress much faster.