Umm without checking, it seems that that when Starbase Earhart (where the Naussican incident took place) it was after graduation where he and his friends were awaiting their first assignments. In "Tapestry" he does tell Riker at the end of the episode that the Earhart incident wasn't his first encounter with Naussicans and he had had an earlier encounter with them during his time in the Academy.
So you mean Picard gets in his first year into a fight with three Naussicans and loses his heart and then a few years does it again with his artificial heart? But then why would avoiding the second fight avoid his dying in Tapestry when he already had his natural heart replaced before????
I would then rather go with the "1-year Academy graduation theory". Within one year, Picard rocks the Academy and wins the marathon too.