Wednesday: shoe sizes

I would like to complain about shoe sizes.  Especially the kids' sizes.  From what I can tell, there are two different measurement systems. 

One goes:

3T(oddler)
4T
5T
6T
7T
8T
9T
10T
11T
12T
13T
3Y(outh)
4Y...

The other goes
4 Little kid
5 Little kid
6 Little kid
7 little kid
8 little kid
9 little kid
10 little kid
11 little kid
1 big kid
2 big kid...

The problem is that sellers, oh say on Amazon, seem to mix and match the size and then put them in numerical order instead of size order.  So we saw a lot of

1 little kid (this is 1Y)
2 little kid (this is 2Y)
3 little kid (this is 3T)
...
13 little kid
3 big kid
4 big kid....

First of all, it took me forever to realize what was going on.  Then it took me a long time to find where the correct size was.  I feel like I'm a rather smart person and should be able to figure out shoe sizes for my child, but I was only 50% sure that we weren't going to end up with baby shoes.  (We didn't.)  I'm also only 50% sure that what I have above is correct, but I wrote it anyway because I'll probably have to deal with it again in a few years and don't want to forget the little I knew.