好像我还是个孩子一样.

as if I were still a child

as if I were still a child 虚拟语气

言外之意就是“我已经不是个孩子啦，已经长大了”，对吗？如果你要表达这个意思，那么最地道的表达应该是：

I was not born yesterday.(直译：我不是昨天才出生的。)

as though I were still a child