Don't worry. It'll probably shrink the first wash and then fit you just fine. This sweater in Istanbul, Turkey is the largest in the world:
A gigantic sweater, approximately 151 feet long and 52.5 feet wide, has grabbed the title of world’s largest sweater in the Guinness Book of World Records. [...]
Knitted for the purpose of drawing public’s attention towards the issue of energy wastage by modern communities, the massive white and black striped pullover was produced by 90 people within 30 days time using over 500 kilograms of wool yarn.