I Gave This Girl A Singing Valentine and Didn't Know Her Reaction?

If you have not read my previous question, you may not understand this question completely. Anyway, when the choir sang a song to her and she read my valentine message, she was all emotional and she might've cried a little bit. I thought a saw a faint of a tear (or like a twinkle of a tear) and she started sniffing a little bit. I just wrote her a very nice message saying that I'm glad and lucky to have you as your friend etc. What does it mean when girls get emotional over this? Is this happy tears? Is this a good or a bad sign?