How do I automate the activation of Python environment
In your ~/.bashrc file, at the end of the file, you can add the source line, so that the environment variables are set up when you open a Bash terminal anywhere. Alternatively, you can have it be an alias, as @user74158 has it below in the comments.
You could also have the python in there, but note that you will be in the Python shell when you start a Bash terminal and will have to exit out every time you want to get back to Bash.