Nothing wrong with the question, but it's not the whole story. Born in the mid 1950s and growing up in the 60s, I might very well have used fountain pens as a child, but I didn't. In fact, although I was vaguely aware of their existence, and they were certainly still available in office supply stores, I have no memory at all of seeing anyone using them. My parents, born in the 1920s, just told me that they were prone to leakage if you weren't careful. They always used ballpoints.
In fact, I didn't even think about using a fountain pen until I was past fifty. I'd discovered that gel pens could be much smoother than regular ballpoints, and happened to read some things about fountain pens as well. So I don't think it was so much a generational thing; I came to them in much the same way that a twenty year old might. If my age played a role, it was more that I already preferred to write by hand, and I was still using cursive.
"So convenient a thing it is to be a reasonable creature, since it enables one to find or make a reason for everything one has a mind to do."
- Benjamin Franklin