In gereral, I've always liked this song. But in these lines is a case of using a word inaccurately in order to make a rhyme. The whole song generally is about "they" (perhaps the parents of the young lovers) thinking the lovers were too young to know the meaning of love. In these lines, the singer contemplates that maybe someday "they" will finally recognize or acknowledge (for the first time) that the lovers in question really weren't too young. Trouble is, that isn't what "recall" means. "Recall" means to recollect something that one was previously aware of, not to recognize or acknowledge something for the first time.