django環境設定について (チュートリアル)

前提・実現したいこと

https://docs.djangoproject.com/en/2.2/intro/tutorial01/#
に従って、進めておりましたが

% django-admin startproject mysite を実行後、

C/mysite % python3 manage.py runserver

を実行時に以下のエラーが発生し進めません。

発生している問題・エラーメッセージ

Traceback (most recent call last):
  File "manage.py", line 10, in main
    from django.core.management import execute_from_command_line
ModuleNotFoundError: No module named 'django'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "manage.py", line 21, in <module>
    main()
  File "manage.py", line 16, in main
    ) from exc
ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment?

該当のソースコード

C/mysite % python3 manage.py runserver

試したこと

①C/mysite % pip install django を実行

Requirement already satisfied: django in /usr/local/lib/python3.7/site-packages (2.2.6)
Requirement already satisfied: pytz in /usr/local/lib/python3.7/site-packages (from django) (2019.3)
Requirement already satisfied: sqlparse in /usr/local/lib/python3.7/site-packages (from django) (0.3.0)

② mysite % python3 -m venv venv を実行
C/mysite % ls
manage.py mysite venv
C/mysite % source venv/bin/activate
③(venv) C/mysite % python3 manage.py runserver を実行

Traceback (most recent call last):
File "manage.py", line 10, in main
from django.core.management import execute_from_command_line
ModuleNotFoundError: No module named 'django'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "manage.py", line 21, in <module>
main()
File "manage.py", line 16, in main
) from exc
ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment?

④(venv) C/mysite % django-admin --version
2.2.6