What does "Three Years She Grew In Sun And Shower" symbolize?
I understand that it is about nature taking a girl's (Lucy) life after having waited for her maturity, but what does all of this mean and symbolize?
I think that Wordsworth's "Three Years She Grew in Sun and Shower" refers to a very young girl who has died. (I surmised she is a a three-year old, based on the title, though another viewpoint is just as likely to be correct.) Nature saw her and her beauty and decided to take her life and make her a part of things like "earth and heaven." Perhaps this is so she would not grow old, but that her beauty would live on in and make Nature more glorious.
As a Romantic poet, I think common themes Wordsworth would have written about would have included nature, enjoying life, the passing of youth, etc. Perhaps the symbolism represents how short our life is on the planet, and how quickly we become a part of nature again after death. In light of this, Wordsworth may be suggesting that we enjoy our time and live fully in the moment.