All my Ds's have had a plateau in weight and height after 18mths-2 years old.

Ds1 is 4.5 years old and weighs 17kg; at 2 years old he weighed around 14-15kg so thats only 2-3kg in 2 years. His height increased a bit more than his weight from about 87cm at 2 years old to 110cm at 4 years old, but still only about 15-20cm in 2 years.

He's quite a tall and skinny thing with no baby chub left. People often mistake him for an older kid or assume he doesnt eat (and he does - ALOT!). Considering my Dh is 6ft tall and skinny Im not surprised Ds1 is like that.