Keep in mind that the Bottle Nipple Chart below serves as a general guideline for choosing a bottle nipple but is by no means an “end-all” solution. It is important to carefully watch the feeding habits of your little one. For instance, is your three-month-old not seeming to get enough from the bottle at feeding time? Moving her up from a Level One to a Level Two bottle nipple may be in order. Adapt your bottle nipple selection to match your baby’s feeding style, regardless of age.