When to introduce bottle?

Ladies I need some input. I have been EBF my 2 1/2 week old baby girl since she was born. She has been doing great with it and gaining weight as she should. I will need to go back to work in 3 months so she will need to be able to take a bottle. When should I introduce one? My sister in law waited till 6 weeks and her daughter refused the bottle and never took one. But I don't want to introduce it to earlier and have her not want my breast anymore. Tell me what worked for you ladies.