Help Purchasing New Fins Please

Hey guys,
This is my first post and I was just wondering if any of you could help me out with my next set of fins. I have been surfing for about a year now and am plodding along very nicely, I have been looking through the FCS range of fins and turns out the fins I have been learning on are small (for people 60kg and I am 90kg) does the size of the fins make that much of a difference, would I find it easier if I went to say the "large" sized fins?
I have a 6'6" board, currently with the TC White-Line fins (I am 6'3" and 90kg) any help would be much appreciated.
This is my first post and I was just wondering if any of you could help me out with my next set of fins. I have been surfing for about a year now and am plodding along very nicely, I have been looking through the FCS range of fins and turns out the fins I have been learning on are small (for people 60kg and I am 90kg) does the size of the fins make that much of a difference, would I find it easier if I went to say the "large" sized fins?
I have a 6'6" board, currently with the TC White-Line fins (I am 6'3" and 90kg) any help would be much appreciated.