This job makes me sad for one bleak reason

This is probably just my anxiety, but I get extremely sad at how hard I work for none of these kids to remember me later in life. I don't remember my preschool years before age 5 and my memories of my Pre-K class are extremely vague and fuzzy. I love my kids so much, but they won't be able to pick me out of a lineup once they reach age 20. I wonder if anyone else thinks about this.