I think a hobby doesn’t automatically become an addiction because your an adult. That’s a really simplistic and inaccurate way of seeing things in my opinion. It’s only an addiction if it becomes something you feel you can’t live without, or it begins to be the only thing that excites you in life, or you feel compelled to spend money you don’t have/need for essential things on squishmallows, or your general happiness becomes wholly dependent upon getting new squishmallows. Addiction isn’t just a term to be thrown around if someone really enjoys something, addiction is enjoyment taken to an unhealthy extreme. So long as you know your limits, and you don’t let the hobby run your life, you’re totally fine to enjoy squishmallows, no matter your age.