eighteen o'clock
Example:
At exactly 1:15 am a dad awoke his child and said, " Happy birthday. Its eighteen o'clock and starting right now your considered of legal age, whats your plans for the future ?"
At exactly 1:15 am a dad awoke his child and said, " Happy birthday. Its eighteen o'clock and starting right now your considered of legal age, whats your plans for the future ?"