I've no earthly clue what the first monster I ever killed was, nor what my character class was. It's been 29 years! I do remember the first character that I ever created was a cleric, who was stung to death by giant bees. He was all alone, poor guy! I'd not really understood the idea of an adventuring party at that point, and after all, there was only me and my brother to play...
Later, when we got a real set of the rules, I rolled up a dwarf, and he and his mule had many adventures.
Gilladian