For me Homebrew installed into a different directory so I had to find that and add that to the PATH. Brew info git does not tell you either so you may just have to hunt for it. For me, the path below worked for me.
export PATH=/usr/local/Cellar/git/2.34.1/bin:$PATH
Then, as others said above, you must add it to your ~/bash_profile so that your PATH is changed the next time you reboot.
Note: 2.34.1 is your version number so you will have to use your version number
You could also create/change a link that is probably already in /usr/local/bin to point to your path. See this link for details on how to do that:
How can I create a symbolic link in Terminal?
Using a link is probably the recommended way to fix this.
which git
in a new Terminal session? – Graham Miln Aug 11 '17 at 14:02