No person shall own, harbor or keep a dog in the Village unless the person obtains an annual license therefor. Such license shall be obtained by July 1 unless the dog Is less than four months old on such day, in which case a license shall be obtained when the dog reaches the age of four months. A person who acquires a dog after July 1 shall obtain a license within thirty days from the time of acquisition or at the time the dog reaches the age of four months.