Command won't change PHP version at all on mac

[Gustah-araujo]

I'm running mac 10.13 High Sierra. My macos came with php7.1 installed, but I'm trying to use 7.3.

This is the outcome of "php -v" in terminal:

I've installed php 7.3 via HomeBrew and now whenever I try to swicth versions, I get this:

First it says that I'm already using php7.3 which is not true since my php -v command returned php 7.1.
Second, it says that is starting php7.3 and immediately returns saying that I am now using php7.1.

Any ideas as to why this is happening?