Anyway-- my point is this-- there is a danger in pushing HG+ kids because of their prodigious memories and way of processing the world. My DD did NOT "get over" it the way a typical child might have. I certainly saw that the other children in the class seemed to recover from their dunkings... but my child was terrified of drowning. Yes-- at 14mo. I knew that she wasn't just afraid of the unfamiliar sensation, but of the DANGER that she could see the environment presented.
This has been my experience with DS2 and is the exact reason I am a proponent of child led everything. My son has the memory of an elephant and the stubbornness of a herd of oxen. Pushing is a losing proposition on every side, be it for swimming, eating, or anything else.