I have a friend who dreams about people before he meets them. Most of the time he ends up dating them, though the dream is a clear warning against that...
It could be 2 things: 1) she reall does exist, and you may meet her in the near future. 2) your subconscious is looking for a way to tell you something. if it's the latter, I'd say that you are wrestling with thoughts on college, religion, and life itself. Seeing her at college is you trying to motivate yourself to learn so you can build a better future for yourself. You having sex in a religious bookstore (wicked irony, btw) may be your way of testing just how forgiving the followers of the faith really are. (btw, religion is bitterly preached against in the Bible. Christianity is supposed to be about love, forgiveness, and relationships. The fire and brimstone approach wasn't recommended; the "way to escape God's wrath" method was used back in that day.) and finally, the beach is a metaphor for life. You're struggling with purpose and meaning, and she is an image your mind has conjured up trying to explain how life can be pleasant. (the ocean is a good metaphor for life in dreams.)
carving her name into your pen was like carving her image into the back of your hand. She represents meaning, and you like meaning; you need it; you crave it.
Even if she is real, and somewhere there's a girl out there dreaming about you, she would still represent meaning. Of this I am sure.
