Reddit mentions of Celtic Myth and Religion: A Study of Traditional Belief, with Newly Translated Prayers, Poems and Songs

Alright, hold onto your seat, there are quite a few haha

Some ecology books, good for your approach to nature itself

• Spiritual Ecology: The Cry of the Earth
  
  
• Original Wisdom: Stories of an Ancient Way of Knowing
  
  
• Mystery Teachings from the Living Earth: An Introduction to Spiritual Ecology
  
  These are more Druid-centric books
  
  
• The Path of Druidry: Walking the Ancient Green Way
  
  
• Bonewits's Essential Guide to Druidism
  
  
• The Druidry Handbook: Spiritual Practice Rooted in the Living Earth
  
  
• The Solitary Druid: Walking the Path of Wisdom and Spirit
  
  These are more historical and culture books about the ancient Celtics, very good for context. Anything by Ronald Hutton I'm going to suggest, though he does tend to have a very dry, academic style. Reading his stuff is more like reading a text book than anything else. So if you do get any of these, pace yourself. I would still suggest getting and reading one Celtic historical book, it's important to know the history.
  
  
• The Pagan Religions of the Ancient British Isles: Their Nature and Legacy
  
  
• Blood and Mistletoe: The History of the Druids in Britain
  
  
• Pagan Celtic Britain
  
  
• Celtic Heritage
  
  
• Celtic Myth and Religion: A Study of Traditional Belief, with Newly Translated Prayers, Poems and Songs
  
  As you go, you'll figure out what works for you and what doesn't, you might end up mixing in shamanism or witchcraft, even wicca, or buddhism, druidry works with a number of other approaches. Keep an open mind, try things, and don't be afraid to ask questions. Paganism in general can be pretty overwhelming, and Druidry has even fewer guidelines than most. Good luck with your coursework!