Either one is a good option, I've seen some spectacular work done using ProCreate on the iPad, but I'm not sure how well that would work on the iPad Mini.
Apple Pencils, from my own research, are actually fairly expensive, some as low as $20, some as high as $100+.
I would honestly go with a tablet to start. You can get an Intuos Draw tablet and its stylus for under $60, and you can use any free art program out there. If you went the iPad route, you'd have to not only pay for the (relatively) expensive Apple Pencil, but also for a decent art app to get a similar experience as you could with a tablet.