My two are 8 weeks old and weigh just over 2.5 lbs. Sophie is 2lbs. 10 oz. and Chewy is 2 lbs. 9 oz. At the rate they have been growing they'll be at least 3.5 to 4 lbs at 12 weeks.
We'll probably be joining the teapot club.
Edited to add: She's a cutie!