Can't seem to upgrade MongDB to 4.0.6

I downloaded mongodb-osx-x86_64-4.0.6 and it self extracted on my mac. I moved it from the Downloads to my User file. I then changed my .bash_profile to include this line
export PATH="~mongodb-osx-x86_64-4.0.6/bin:$PATH"
But when I type mongo --version it still says 3.2.8.

What am I missing?

I unstalled MongoDB to try to install it again. But I can’t install it. I follow the directions, but bash won’t recognize the keyword mongo