在我小时 means "when I was young" or "during my childhood" in Chinese.
来源：这个短语是由两个单词组成的：在（zài）和小时（xiǎo shí）。在是一个前缀，表示时间，位置或状态。小时是指童年或幼年时期。
英文例句及其中文翻译：
I used to play with dolls when I was young. 我小时候玩过娃娃。
My parents took me to the beach every summer during my childhood. 我小时候的每个夏天我的父母都带我去海滩。
I remember going on long car rides with my family when I was young. 我记得小时候和我的家人一起开车去旅行。