M.O.
Honestly, she sounds like a toddler. You could fit those reactions into the rubric of sensory issues, but either way, many, many little ones have some kind of fear/reaction that seems irrational to adults. It's a phase, like monsters under the bed. They just about all outgrow it within a few years.
My son was no fan of sand either. Was petrified of wind. Pretty much, the world ended if he got a wood chip in his shoe. And, he's outgrown it all, though he still struggles with swimming. What's stayed is the good stuff -- he's a cautious, thoughtful kid. Thinks before he acts.
I wouldn't force it or make a big deal out of it. Just make things a game, like you've been doing, and don't react too much if she acts scared.