Ahhhh ... fins ...
When I began to learn to swim, at about 54 years old (never swam as a kid), if I hadn't gone to using fins I would not have progressed to where I am now. Others may disagree. However .... be cautious if using fins. My experience was that it became difficult to "free" myself from using fins. I would say "that if I were to fall out of a boat - that I would want my fins before a PFD...." But, now about 8 years since beginning the learning to swim process .... I only use fins for a bit of play time .... very seldom. Fins can become a crutch for correcting poor balance. Probably would have been better to struggle through without the fins. But ..... Also - if you do use fins, try to finish every swim with 5 or 10 minutes swimming without the fins.
If you're not swimming; then you should be skiing......