That very much depends on what your interests are. Both Django and Data Science are very popular fields. Data Science is more based on working with raw data, cleaning, transforming, normalizing it, and then applying algorithms to extract important and useful information from it.
Django on the other hand is used to build the backend of a web application. It is used to create a website based on a specific set of business requirements.
I would suggest that you try both out and then pursue which one you feel more comfortable with.
Here's a video on data science
and here's on on Django
Try them both out and then pursue one of them.