Is it possible to make a mobile app in Django?
Yes. There are a couple ways you could do it

Use the Django Rest Framework to serve as the backend for something like React Native. 
Build a traditional website for mobile and then run it through a tool like PhoneGap. 
Use the standard Android app tools and use Django to serve and process data through API requests.
I was wondering if it is possible for me to use Django code I have for my website and somehow use that in a mobile app, in a framework such as, for example, Flutter.
So is it possible to use the Django backend I have right now and use it in a mobile app?
So like the models, views etc...