Paisa from Medellin, Colombia here (currently living in Bogotá though).
Antioquia/Eje Cafetero will definitely be the region with the largest 'No' voting population. I would even think that the region with the next largest 'No' voters would be Bogotá DC. All of this is exactly because of what you say.
But let me tell you something: Even in Medellín, there's a correlation between being a young and studied person with voting 'Yes'.
The best analogy for me is the Brexit. Where old and uneducated people ruined the UK for the future generations.
Antioquia/Eje Cafetero will definitely be the region with the largest 'No' voting population. I would even think that the region with the next largest 'No' voters would be Bogotá DC. All of this is exactly because of what you say.
But let me tell you something: Even in Medellín, there's a correlation between being a young and studied person with voting 'Yes'.
The best analogy for me is the Brexit. Where old and uneducated people ruined the UK for the future generations.