My 27 month old will not stop shoving anything and everything in her mouth. It doesn't appear to be teething related because it is pretty much nonstop. She started early - around 4 months - and hasn't stopped since. To the point where I worry about leaving her alone with anything smaller than her fist. Is this normal or could there be some kind of issue I'm missing? She doesn't have any issues with eating or any sensory problems, and I really thought this would stop by now.