The boy's knees are out of focus...her necklace, the closer side of it, is slightly out of focus...the focus is not quite placed right. It's slightly OOF. I would agree...the f/stop used has not given "quite" enough room for them to be in 100%, critically-sharp focus. For example, look at the chair-back on the right hand side of the frame, and see how sharp that woven part looks...they are CLOSE to being in good focus. Looking at the boy's knees, you can see the foreground defocused zone, as it is called...and then the closer edge of her necklace STARTS to come into almost-acceptable focus....but her face and hair on her forehead are not quite yet in the solidly IN-focus zone...to me, I see visual clues that the BEST focus is actually BEHIND the plane of her face. This is "close", but still what I consider "missed" focus. Now...in hand grenades and horse shoes, close counts...in THIS shot, I see what is called "back-focus". It is not horrible back-focus, but it is,indeed, back-focused.