Without knowing a persons age for sure it can be very hard to tell how old they are. I am 34 years old but have had many people of varying ages some older and some younger than me think that I was as young as 18 which is 16 years off.Many people miss my age by 5 or 6 years which is about reasonable for the average person guessing another persons age.
Both of these girls could be as young as or younger than 18 I'd be very surprised if either of them are over 25 though judging by their apparent rank you can safely assume that they at the most 20 or 21.I dont think that the minor differences are going to make a 40 year old woman look like she is 18.
Also
every human being looks different do to genetic variation.
P.S. I kind like the second woman more though dont tell my wife....her parents are from the Ukraine so shed
have my balls for checking out a younger and Russian woman.....