Just me personally I wouldn't shoot for anything over 20-30lbs in the first year. And even that is if you're training hard in the gym and seeing your strength increase rapidly.
There's only but so much muscle you will build, through your entire life, training naturally and frankly that's not going to happen all in one year or even 3 years. So don't be in a hurry to get big. Learn to train, learn the big exercises, learn to love the gym. That all comes with time, just like your weight gain should.