My dd is 25 months. She wears mostly gymboree size 12-18 months. She was exactly 16lbs at her 1 year check up and 21lbs 1oz at her 2 year check up and 32 1/4 inches. My dd1 is 6 years old and was similiar 16.5lbs at a year but jumped to 23lbs at age 2. Somewhere from age 2 where I believe she was at most 10% for height she jumped to 50% for height at age 3. She is now fairly average for her age just skinny. (50% height/7 % weight at 6) She needs size 6 for length on pants and has to be slims which are often too big in the waist even then. My dd2 was bigger than my dd1 at birth by 1 1/2 pounds and they are 48 months apart but dd2 wears a size smaller than dd1 did so it is really hard for me to predict sizes a year ahead.