Help with phrase please

[jimmypop]

How would I say "before I knew, everybody was there." I'm having trouble with the "before I knew it" part. I was saying ""Antes que lo supiera..." But I guess that wouldn't be correct in this case? Any help would be appreciated...

[Rusty]

Antes de que lo supiera ... (todos llegaron)

[JPablo]

I take that you could also use something like,
Antes de darme cuenta (as in "before I realized")
Cuando quise darme cuenta, could also work. (Literally, "When I wanted to realize").