The governing body of any county, city or town may, by ordinance, provide that every person 14 years of age or younger shall wear a protective helmet that at least meets the Consumer Product Safety Commission standard whenever riding or being carried on a bicycle, an electric personal assistive mobility device, a toy vehicle, or an electric power-assisted bicycle on any highway as defined in § 46.2-100, sidewalk, or public bicycle path. Violation of any such ordinance shall be punishable by a fine of $25. However, such fine shall be suspended (i) for first-time violators and (ii) for violators who, subsequent to the violation but prior to imposition of the fine, purchase helmets of the type required by the ordinance. Violation of any such ordinance shall not constitute negligence, or assumption of risk, be considered in mitigation of damages of whatever nature, be admissible in evidence, or be the subject of comment by counsel in any action for the recovery of damages arising out of the operation of any bicycle, electric personal assistive mobility device, toy vehicle, or electric power-assisted bicycle, nor shall anything in this section change any existing law, rule, or procedure pertaining to any civil action.