I answered a couple times to others about NAM and people found my answer helpful. So, I pasted the link below.
I was in it in Florida and it was great. My friend was in it then I did it too.
If you go to youtube and search for "National American Miss" you will find lots of vlogs and things that girls that have been in NAM have uploaded. I'd say that is a pretty good place to look.
As for your dad, well, I guess it is a parents job to protect you. So, do not take it too personal. He is just doing what he is supposed to do. Problem here is that he does not actually know about this subject, so he is just being quick and cautious. That's ok.
I'd say go with your mom to the open call and see what it is about for yourself.
I really liked it and it did a lot for my confidence. My dad liked NAM because it teaches you how to handle yourself in job interviews. And, duh, he wants me to get a job when I graduate.