How would you react if one day we made alien contact?
I'd be excited, first and foremost.
Depending on the nature of the contact I might also be worried, or even scared. Or I might be very happy.
The premise of your hypothetical is that there is real alien contact between
us and some aliens. I assume you mean proper, verified contact, not another youtube video about a guy filming a light in the sky.
I will believe anything, when there's sufficient evidence that it's true/real. I'm very open minded, in that way.
How would your life change if at all?
Again, it would be much depend on the nature of the contact. It would depend on what the aliens came here for, for instance. If they just landed their spaceship on the White House lawn, said a quick "hello" to the President and the world's media, and then got back in their spaceship and left permanently, my life probably wouldn't change very much.
On the other hand, if the aliens started dropping nukes on our cities, my life would change a lot, I expect.