Why Leah Won't Be Allowed to Date Until She's 25

Teenage romance:

Capulets:  We hate the Montagues!
Montagues:  We hate the Capulets!
Romeo, a Montague:  I'm so depressed.  Maybe I'll go to a ball.  (sees Juliet at the ball)
Romeo:  Behold, what yonder hot pre-pubescent girl is that?  Would that I were a glove upon that hand, that I might be better looking than the one she has on.
Juliet, a Capulet: Oooh, Romeo, wherefore art thou so adorable, Romeo? (Juliet swoons right off the balcony)
Capulets:  We hate the Montagues!
Montagues:  We hate the Capulets!
Romeo:  Juliet, let's get married even though our families hateth each other, we've only known each other for three minutes, and our combined ages would not make us old enough to vote...eth.
Juliet, to her nurse (using a squeegee on the glass so that the light can through yonder window break):  Squeeeeeee!  I'm getting married!  But my family won't like that, so I think I'll pretend to be dead so I can escape with that guy I just met.  You know the one I'm talking about...?  The guy with the thing for balconies...?
Nurse:  Romeo?
Juliet:  Yes!  Romeo.  How could I forget?  (runs off to pretend to be dead).
Romeo:  Juliet is dead?!  Oh, cruel world!  How could you take her from me before I found out what her middle name is?!  (takes poison and keels over)
Juliet:  (wakes up)  Romeo, you're dead?  Why didn't you text me first?!  (stabs herself in the chest)

FAST FORWARD 400 YEARS

Bella:  Who is that hot, strangely sparkly guy?
Edward: (brooding look) I've been stalking you around town and watching you sleep.
Bella:  Oh my gosh!  You are soooo romantic!
Edward:  I'm not sure I can stop myself from killing you.
Bella:  I don't care.  Let's go out in the woods together, by ourselves, and I'll put my throbbing carotid artery right next to your beautiful, pointy teeth.  Don't worry, I won't tell anyone how dumb I am.
Edward:  You smell so delicious.  Way better than that pig I slaughtered for dinner.
Bella:  Oh, Edward, you know I can't resist you when you talk about slaughtering pigs.
Edward: (brooding look) I'm dangerous.
Bella:  I know.  Climb in bed with me.
Edward: What about Jacob? 
Bella: Oh, he's just a boring friend who doesn't want to kill me.  Not like you.  I mean, what passion could there possibly be in a relationship where my life isn't in constant danger?
Edward: Marry me.
Bella: I don't want to make that kind of commitment. How about I become a vampire for eternity instead?

I rest my case.