Jace hasn’t been all that controlling up to this point, obsessive sure. I mean, the whole stalking, attempting kidnapping, and of course, the watching her sleep crap was more than a bit obsessive on his part. I have on good authority from my friends who have read the rest of the series, that it gets worse the more we get further into the books. I wanted to point this out because this to me , this is the initial seed of Jace’s controlling behavior.
He’s controlling the way she looks. He doesn’t care that Isabelle spent a considerable amount time and effort to get Clary’s hair into that updo, He just took the bobby pins out of her hair. He put the necklace on her and didn’t even ask her opinion on it.
Now, normally this would stick out to me, but if you add this to Jace’s already horrible behavior towards Clary. Finally, if you take in the tone and the subtext of this passage and it just all adds up to Jace being a creepy controlling and obsessive douchenozzle.