Around what birth year do people generally have little to no familiarity with the concept of memes?

Memes have been a huge part of internet culture for decades, but not everyone is immersed in them. At what point do you think people start to have little to no awareness of memes? Is it more about birth year, internet exposure, or something else? Curious to hear your thoughts, especially if you've encountered someone who had no clue what a meme was!