Short answer: No.
Long answer: From what I recall from the anime, several strong Pokémon have to use Water Gun to force a steel plate from a wall, so I can't imagine one weak Squirtle punching a hole through your chest with a Water Gun.
Moreover, there is no way a Squirtle is even able to use Water Gun at level 3 except in gen I. Water Gun is not learned until levels 13 or 7 (depending on the generation), does not pass down through breeding and Squirtles do not learn it through TM's except in gen I. Source, you can check all gens.