[Definitely not the reaction of one who enjoys this kind of thing. But the rest is entirely in line with the behaviour of a teenager, and he smiles at it. At least one of them is having fun.]

'Practically nineteen'. How could anyone doubt your maturity. [He says it mildly, teasingly, and then sets the knife aside to pull down a sleeve and dab her wound. His shirt is already dotted with blood from his first time in this room, so he isn't troubled by the stain.] This isn't an easy scenario to get into. So dreary, and it smells like sweat and blood in here- not suitable at all for romance. You might have better luck writing about it.

[He tsks and applies the knife again.]

That's how you do them. [Compliments, that is.] Do you write about it? Romance?