Sounds about right. From wiki:
"Maine Coons are one of the largest breeds of domestic cat. Males weigh from 15 to 25 lb (6.8 to 11 kg) with females weighing from 10 to 15 lb (4.5 to 6.8 kg).[17] The height of adults can vary between 10 and 16 in (25 and 41 cm) and they can reach a length of up to 40 in (100 cm), including the tail, which can reach a length of 14 in (36 cm)[18] and is long, tapering, and heavily furred, almost resembling a raccoon's tail.
The body is solid and muscular, which is necessary for supporting their own weight, and the chest is broad. Maine Coons possess a rectangular body shape and are slow to physically mature; their full potential size is normally not reached until they are three to five years old, while other cats take about only one year."
