What was the reason given to you to start on stage 2 first?
I feel you should go according to the age group and start with stage 3. Reason being that nutritional components will be more suitable for your child. Eg, stage 3 has more protein than stage 2 because protein is what a toddler needs to help them beef up and grow. Stage 2 still contains some level of fats which babies require before the age of 1.