at first
Initially. At first, we planned to go to Florida, but now we're going to visit family in Montana instead. I didn't like Tom at first, but the more time I spent with him, the more I enjoyed his company.
at first
initially; at the very beginning. He was shy at first. Then he became more friendly. At first we chose the red one. Later we switched to the blue one.
at first
Initially, at the start, as in At first the berries were green, but when they ripened they turned bright red. [Second half of 1500s]