>> Fandom Firsts/stories that really stuck with me/past fan activities/people I've met in fandom who've had an influence on me <<

Oh, that sounds great. I haven't seen many people doing those in the past, but they really capture the culture of fandom rather than the content.

>> Friends only, but I'd be making these posts public <<

That's a great solution. I've added "friends only except public challenge posts" to the list of options.