Ummm... hate to break this to you, but Romeo and Juliet were only approx 13 yrs old. I admit I have not read this, but it sounds like it was based off Shakespeare's play. And they got married (R&J I mean)
Nightfall- Romeo was 15 and Juliet was 13.
Actually Romeo's actual age was never revealed (just checked my copy of the play). But I was just listing an example from the top of my head. :D (and Googled it too...) LOL
They are only freaking 12 years old, right?? Oh well, I'm outta this shit