( dany looks 18 or so on television so please stop telling me things from the book. I plan on reading it soon so spoilers like that, while small, lessen the experience. I want to find out where the book and show differ myself.)
If a characters age being different in the books is really that huge of a plot point for you, I'd highly recommend not reading anything about GoT ever again until you read the books. People seem to slip actual spoilers into all sorts of things about it without even realizing.
It seems your lack of understanding into human passions is what keeps you from understanding why Dany and Drogo worked so perfectly.
...Wow. 'Oh I see why you don't agree with me, you've never had sex'
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**R.O.B.A.Z.O.I.D**