Tweenagers do not have disproportionately large heads in the way babies and toddlers do, their shoulders are bigger than the widest point of their head. And their limbs and bodies are much much longer. Medium sized gaps are dangerous to very young children because they may try to crawl backwards through them (or roll/wriggle into them in their sleep) and their body fits through but their head does not, which puts dangerous amounts of pressure on their neck, posing an asphyxiation risk. Also a baby/toddler does not know how to free themselves by reversing the way they got stuck, whereas an older child barring disabilities will know this (or as others pointed out they could shout for help).
So yes, you're well past the age where this would be considered a risk, that age is probably passed by about 5 years old.
In any case this gap looks wider than the size which is disallowed - the risky gap is when it's wider than 6.5cm but smaller than 20cm or something like that - it might be 23/25cm but I can't find the source now. If the young child's entire body including the head can fit through, then it's still a risk for falls (for things like bannisters or bunk beds) but no longer for entrapment.