puppy weight?

Question
I have a female lab that is 7 months old, she weighs about 51 lbs. is that about the weight she should be. I was told mom was about 70 lbs and so was dad. How long do they continue to grow? Also she is not a huge eater like my old lab, about how many cups of food should she be eating a day. Sometimes I worry she does not eat enough. She is not a lab that will eat every bowl of food you put in front of her

Answer
Be happy that she is not the type of lab to eat everything in front of her.  You'll end up avoid problems like her eating garbage and getting an obstruction.

Pups continue to grow to about a year and then that 2nd year, they develop a bit more.  By the time she is 2, she'll probably be between 60-70#.