My youngest is also much further ahead in the “building a resume” game than her sister was
Can you flesh this "resume building" thing out for me?
It's basically showing authentic, sustained commitment to something - optimally with an academic or artistic connection but not necessary
For my kid, it was studying Arabic.
He started studying in middle school through an online course offered by JHU's Center for Talented Youth, then got a scholarship to study Arabic in Morocco for a summer, then did some translations during high school (where Arabic wasn't offered) and then wrote an essay that tied together his interest in studying the language with what he wanted to do in college
It made for a coherent narrative that showed him to be a smart, committed student. In my opinion, this was much more valuable in the college admissions process than signing up for yearbook, choir, etc, to just lard up on a list of activities that didnt't really mean anything. So find something you kid really likes to do, support their involvement in it, and see if there are volunteer opportunities to then build on that involvement that reinforce the story you're trying to tell.