as a child; when one was small — used to refer to events or habits from one's childhood.
小さい頃、よく祖母の家で遊んだ。
When I was little I often played at my grandmother's house.
小さい頃の夢を今でも覚えている。
I still remember the dream I had when I was a child.
小さい頃は虫が平気だったが、今は苦手だ。
When I was small I didn't mind insects, but now I'm not good with them.