To a Daughter Leaving Home...

I read a poem which is called To a Daughter Leaving Home and as I read this my mind began to ponder on what it will be like when I have a daughter and for whatever reason she has to leave home. This poem talks about a woman's daughter who is riding a bicycle and who just keeps on riding but never stops. The mother lets her keep going. What causes a question in my mind was within this poem the mom at the end waves goodbye to her without a care in the world. It really confuses me and just really don't know what to think about it. I think in todays culture the daughters are getting out too early which causes them to sin and in this story the daughter seems really young. I'm sure this is meant to be a poem for lets say a college girl, but it also could be meant for someone younger. In the poem it says, "I kept waiting for the thud of your crash as I sprinted to catch up, while you grew smaller, more breakable with distance, pumping, pumping for your life..." These few lines confuse me because I wanna think that the mom cares but at the same time if the mom really cared she would've kept going until she caught up with the daughter. I view this as being something where the mom is letting her daughter go but yet at the same time who would let their daughter leave home at eight years old?