I am honestly not sure. Never really looked at it as normal or not just went a long with it with each one at different times. LOL I have 4 and two are very very smart and I think the one was about 14 months and the other about 12months. But my oldest didnt till he was about 15months(he actually was too busy standing at 8 months and walking at 9months Ahhhhhhh!!! LOL)
Please make sure those plastic coins are too big to go in mouth...I have had those get stuck in the kids mouths before. Just a little word of caution from a been there done that.