We waited until 4 weeks
We were told to wait until the baby was 4 weeks old to introduce a pacifier or bottle if we planned to nurse. That was so my milk had come in and Avery learned to latch well. It also helped us learn her schedule.
I stay home so I didn't really NEED to give her a bottle, but I wanted to make sure she would in case I needed to be gone. It also helped me learn how much milk was normal for me. That way I knew if my supply was dropping. I pumped once a day and let my husband give Avery a bottle during that time. It gave me a nursing break and let him bond with her! We did that for several weeks and then I just pumped when I needed to be gone during a nursing. Avery is still nursing and we've never had a problem with nipple confusion.