The first week of your newborn’s life is the best time to photograph them, ideally between 5-12 days old. Babies this young are still happily curled up and sleep deeply enough to be safely posed in your favourite poses and props.
Older babies are bigger and their bodies become more comfortable in straighter positions. Should your baby be a little older we can still take some amazing images, they would just be posed differently to accommodate them. Babies after 12 days are at risk of Baby acne and not settling. For very bad skin I would charge an additional fee, editing the images can take three times longer when skin is bad.