'Year old' in the Bible

Then when she had done so, she took him with her, with a three-year old ox and an ephah of meal and a skin full of wine, and took him to the house of the Lord at Shiloh: now the child was still very young.

And you are to give a lamb a year old without any mark on it for a burned offering to the Lord every day: morning by morning you are to give it.

With what am I to come before the Lord and go with bent head before the high God? am I to come before him with burned offerings, with young oxen a year old?