The number of trustees of any church specified in § 33-268, which shall in no case be more than fifteen nor less than three, shall be determined by a majority of the electors at the first election by the church and before the votes for trustees are cast, and shall remain the same, unless changed by two-thirds of those present and voting at any subsequent election. At the first annual election the inspectors shall determine by lot, and as nearly as practicable in equal numbers, who of those elected shall serve for one, two or three years. At each election thereafter the electors shall elect trustees for three years to fill the places of those whose terms have expired.