I act like I am smart, but I am much dumber than they think
Why do you act like you're smart?
It will make me feel better if they believe I am smart
You should give yourself more credit. You're probably smarter than you think, and it doesn't help anyone in the long run to pretend to be something you're not.
That might be true. I just don't feel the need to show how dumb I am.
I think you should just try and be yourself in front of these people.