A Thai girl born in Isaan or Norther Thailand is a completely different girl from one born in Bangkok. Bangkok Girls are much more educated not because they are more likely to go to University but because the schooling system in Bangkok is much more developed as is the quality of the teachers in Bangkok.
Bangkok Girls are much more fashion oriented have more style and class than their country brethren. You can always tell a Thai Girl who was born and raised in Bangkok as much as you quickly spot a girl born and raised on the farm in Eastern Thailand. Bangkok Girls are always taller are not white nor are they dark skinned they are more a yellow color than anything else.
Just because you are a Thai Girl born in Bangkok doesn't mean necessarily that you come from a middle class or wealthy Thai family. You can deduce though that you have more opportunities than girls born outside of Bangkok. For Bangkok girls working in Nana Plaza or Soi Cowboy is the last of their dreams and as you'll see if you go to those places you won't find anyone who was born in Bangkok working there, for the dream of having a rich farang boyfriend is something only country girls dream of.
So Bangkok Girls dream of different things, mostly being a model or movie star, they aren't as interested in having farang boyfriends unless of course they have studied humanities or tourism, Bangkok Girls have a lot of western characteristics to them than their country peers.
Why Bangkok Girls are so Unique
Bangkok Girls are more unique than Thai Girls from the rest of the country. They are not just unique because of education, status in society or anything, the difference is rooted in their history as well, Bangkok Girls are unique because they were born from a different mix of Thais, you can see it in their features the way they look is much different to the way other Thai girls from different parts of the country look. Bangkok Girls are even thinner than girls from the north who are much chubbier and more Chinese looking with pale skin.
Bangkok girls know how to party too, they know all the best clubs in the city, have been to most of them and are more willing for casual relationships, Bangkok is just like any other city and the people who are born here are much more westernized than you'd think they were.