I have lice and I've been wondering how long it'll take to be considered "clean" again.

Well, I had these huge plans for a big sleepover with my best friends because I’m going to have the house nearly all to my self (my dad’s gonna be in the basement). But then I got lice. My mom was saying that as long as we found the last louse 3 days before the day of the party, it would be alright and we wouldn’t have to postpone it. Now she isn’t convinced that 3 days is long enough. We’ve been searching high and low on the net for info about this. Does anyone have some information? It’s not just that we’re wondering about how long we’ll have to be clean to be considered clean before my friends will want to come over, we’re wondering how long it takes to be sure you’ve gotten rid of the lice.