QUESTION ABOUT HOW YOU CATCH LICE

So long story short my moms husbands grandchildren are staying with them right now due to issues at home.

My daughter also stayed over there for a sleepover last weekend and we just found out today that the granddaughters have head lice.

So obviously I immediately checked my daughter but I didn’t find anything (I checked all around her hair line, close to the roots throughout her hair looking for eggs/any signs but she has pretty long, somewhat thick hair)

So I guess my question is - When coming into contact with someone that has head lice, would I notice by now if she had got it?