I generally try not to judge parents for asking questions that--to me--make it seem they have never been nor met a child before their own appeared in their lives; variation and experience vary so much and mothers are held to such a ridiculously high standard that paranoia becomes second nature, etc....

...but if you have to write to an advice columnist to find out how to talk to a seven year old about them having a crush, which is such a universal part of childhood it's sitcom fodder, the next eleven years of your life are going to be a hellscape and you also may be a pod person.

I just checked my DW, and Child's greatest hits from about sevenish to ten years old included:
1.) why the Palestinian and Israeli people always fighting and why they can't just all live together? - his school had a Palestinian speaker that day and boy, would I have appreciate a heads-up from the school to brush up on the last five thousand years of history of the Middle East and the reasons for the creation of Israel after World War II so at that moment he wouldn't know more about it than I did.
2.) His human cloning phase, during which the subjects included feasibility, ethical considerations, morality, the most viable parts of the human body from which to get DNA, and creating human-lizard army. Ages seven and a half to like, now.
3.) why he couldn't make homebrew napalm in the backyard from styrofoam and gasoline
4.) in retrospect, the completely predictable series of events following his acquisition of his first chemistry set.

What do you say? You say 'what are [they] like?', 'what's their favorite color/reptile/dinousaur' and make affirmative noises and smile and be incredibly grateful, like I was, because it's not midnight and your eight and a half year old didn't just wake you up, worried, wanting you to negotiate peace in the middle east a full day before amazon delivers the books amireal (among other blessed individuals) recommended in response to your honestly hysterical email, and also, napalm isn't involved.