actually no a baby cant go over 25 pounds on a v4.5 i have mine up and working and my baby cant go over 25!'Normal'? There is no 'normal' weight for a child.
Each character has a base weight (all toddlers' are 10lb). Their weight cannot go below this, but can be anything between the base and 99lb. On V4.5 this makes no difference to the growth pattern, etc, so you don't need to worry about weight.