If you get all of your family medical history together ahead of time it will help a lot!! You know your baby the best so get a list together of what concerns you have. Don't be afraid to ask them a lot of questions too!
Agree with previous posters.
TONS of questions def. bring toys/snacks/other things for your little one to do. Our first appointment took 2 hours.
They might do blood work (they did with ours) and a quick medical exam.