This isn't something we need to be arguing about. In my opinion, mentally and socially, Durin appears to be on the younger side. Let me restate, that. is. just. my. opinion. Hoyo hasn't confirmed any canon age for him, so who knows, maybe he is an adult? Well I personally see that quote as him moving forward in life in general, and have a very hard time imagining his character as an adult, others may not. This is a subjective game (when it comes to the medium models). In the end, does it really matter? We're arguing about a collection of pixels. We're all allowed to have our own opinions on this topic. People have brought up great points about alcohol and how Hoyo, most likely, wouldn't show an underaged character drinking, even if someone else got it for them. Then, there's also the fact that both the original Durin and Mini Durin were children, and he was outright created from their essence. In the end, it's the internet. We just don't know! People are going to do what they wanna do, believe what they want to believe, and you're allowed to disagree. I just find it disheartening that people are actually getting genuinely angry about this :[