One of these two women is 4 years older than the other.

One is a minor. One is not.

Of course you can tell which is which, right?

https://m.primal.net/IBMl.jpg 
https://m.primal.net/IBMm.jpg 
https://m.primal.net/IBMn.jpg 
https://m.primal.net/IBMo.jpg