I'm in the process of picking an ergo baby carrier. I have a 4 week old barely 7 pound baby girl pictured below :) I'm wondering if I absolutely need the infant insert?? Or does it come with the pillow for their bottom?? If not I'll save the extra bulk and money and just buy the carrier. I've borrowed one briefly once before and loved it!! Any advice, input two cents is appreciated! No negativity please!!