What to expect?

Kristen • First time mommy to be. Expecting our baby boy January 2016 ❤️
So I'm a first time mom and I have my next doc appointment on the 29th of this month. This doctors appointment will be the first time I get measured. When I go in I'll be just shy of 17 weeks and I'm wondering what I should expect at my appointment. 
Tanks ☺️