This seems ok to me. Over time you might come to regret it if you have many scripts and they want to use different package versions...
Another approach could be to write a shell script which loads the virtual environment and then starts the main script. something like
cd /home/rimu/path_to_my_script/
source venv/bin/activate
python myscript.py
Put your shell script in ~/bin and ensure that ~/bin is in your $PATH.
Sweet as!