948.60(3)(c) reads (my annotations in [brackets]):
"(c) This section [meaning the entirety of section 948.60] applies only to a person under 18 years of age who possesses or is armed with a rifle or a shotgun if the person is in violation of s. 941.28 [relating to short-barrel guns] or is not in compliance with ss. 29.304 [prohibition against persons under 16] and 29.593 [prohibition against hunting without a license]."
So literally 948.60 does not apply, including subsection 948.60(2)(a) that you quote.
948.60(3)(c) reads (my annotations in [brackets]):
"(c) This section [meaning the entirety of section 948.60] applies only to a person under 18 years of age who possesses or is armed with a rifle or a shotgun if the person is in violation of s. 941.28 [relating to short-barrel guns] or is not in compliance with ss. 29.304 [prohibition against persons under 16] and 29.593 [prohibition against hunting without a license]."
So literally 948.60 does not apply, including subsection 948.60(2)(a) that you quote.