First TV show I had self-insertion fantasies about: Thunderbirds, I think
First fandom in which I interacted (online and in person) with other fans: Literary SF fandom generally - there wasn't really much else in the UK in the seventies.
Pairing in the first (m/m) slash fanfiction I read: Kirk / Spock, in the fanfic (and later play) Spock in Manacles which I saw at an SF con then bought. It's a fun musical with a lot of parody songs.
First RPS/RPF I read: Never into it - the first I can remember is something which used the "Kevin Sorbo is actually Hercules" shtick from Hercules / Xena.
First fanfiction I read that made me think, YES, this is exactly the kind of fanfiction I'd like to write... Something in the Buffy fandom by rozk, I think, but not sure which.
Pairing in the first fanfiction I wrote: I think it was a Buffy / Authority crossover, Jenny the Vampire Slayer which mentioned (in passing) Jenny / Willow and Jenny / Angel as part of her 100-year career. I seem to have published 3 stories the same day, which makes me suspect that there was some sort of reset on the dates, but the other two didn't have pairings anyway.
First OTP: Something I don't really do - I don't write shipper fiction, so pairings tend to be canon or whatever best suits the needs of the plot. The first that was fairly integral to the story was in Family Issues which resolves around Willow / Tara.
First RPS/F OTP: Don't do them
First fannish friend I met in person: rozk (but long before I knew of her interest in fanfic)
First character I formally roleplayed: Assuming this means a canon fictional character, the only one I've ever roleplayed was Horace Slughorn in a livejournal story game - I had to drop out, mostly because most of the players were writing steamy sex scenes, and (a) Horace really doesn't work for them and (b) most of them were deadly dull.
Apart from that I've done a ton of more normal roleplaying games - I can't begin to remember who my first character was, I think he was killed within about five minutes.