Lets talk shoe size please!

MJN9510

DD is 9 months old and she is still in a size 2 which I think is typically for 3-6 month olds.  Some of the size 2's are too big and i am not sure if that is because she has more narrow feet or what.   I bought some super cute sandles that said for age 3-6 months as a size 2 but they just fall off her feet.  I would think her feet would be bigger than this by now.  What size does your LO wear?  i am starting to wear shoes on her more now that she is standing and she walks if we hold her hands so i want her to get used to what shoes feel like on.