In agreement that accessteacher simply states it in the best possible way, I feel as though I can offer something a little different.
My daughter, 14, just broke up with her first "boyfriend". He immediately began to tell her that he loved her. Her response? We are too young to know what love is. My daughter is her mother's child. (I have taught her well--not tooting my own horn, but she really does have a great head on her shoulders.)
Now, her "ex" loves her best friend. This has caused problems--as I am sure you could imagine.
Teenagers, today, are simply not cognitively developed enough to understand the concept and consequences of love. This alone is dangerous.