My baby girl is 3 weeks old today, and I've been pumping for about 2 weeks and a few days. When I pump, she drinks out of a Phillips Avent bottle with the size 0 nipple. I saw that size 1 is for 0-3 months. When would be a good time to test out the size 1 and see how she does? I only have 2 size zero nipples but I have 4 or 5 size ones so it'll be more convenient. I just don't want her to get too much at a time and choke or something. Any advice?? Thanks in advance!