At least in my country (Spain), it is not at all age related. No one uses sms for communication. I just checked a local source and Whatsapp usage is 97% among the young lowering to 87% among the 70+ group, with the practical totality of the others choosing just calls or no phone usage.

If you know a European country where SMS are the norm, can you share which one? As I said, I don't know a single one, but they might exist.