Well I did raid Maraudon when I was a lowbie, but first raid was Molten Core.
10M Scholomance before it got reduced to the 5M version.
And my very first PvP raid was at lvl 13 or so in Ashenvale. Was shitting my pants when I saw my first Moonfire getting shot at us by some elf druid. Didn't even know who the enemy was or what they looked like.
Karazhan here, damn good times.
Either Scholo or Baron.
**Or our epic wannabe raid on the undercity back when world pvp was awesome and exciting and guards wouldn't 1-shot everyone.
Karazhan. Best instance ever, really.
Karazhan, have fond memories of that place (althought by unspoken consent no one ventured into animal quarter)
10 man strat dead side. on my enhancement shammie. had no clue what i was doing, but had fun doing it!
loot reaver.. :P it was interesting
MC on my mage. R.I.P.
10 man Baron or Scholo, can't remember which, lol. Way back in like March/April 2005
Naxx10, Kel'Thuzad. My very first raid experience, thrown into the second 10man team of a "soon to be a 25man raid" team. Ended up dead in the very first void zone since I misunderstood the raid leader. Good times.
We did eventually kill KT a few pulls later. \o/
UBRS at 54... we actually full cleared with me being that low too O.o