What is waiting for me at arrival?
You definitely don’t need to expect a huge cultural shock at arrival, because Colombia has large modern cities. There is WiFi on 90% of all public places; you can find Nutella in all supermarkets (expensive though); you will find stores and brands very much like in your country; there are good transport facilities and so on. Even Medellín has a metro (above ground) and cable cars. Nevertheless, the difference between poverty and richness in Colombia is much bigger than in Western countries.
The moment you visit smaller villages on the countryside, you will experience that time has stood still. You will see man and horse, working farmers on their land and poverty. But there is a peace-loving atmosphere all-over!