Good First Car

I’m turning 16 in a few months and am looking for my first car. I learned how to drive on my brother’s 2001 manual xj and of the cars I’ve driven, I liked the manuals the most, especially my brother’s Sn95 Mustang and my parents have offered to match any money I put into buying a car. I have a $20,000 budget and am looking for a car that is manual, can fit 2 people easily, and four people occasionally. As a teen driver, I need at least airbags for safety. I grew up working on my dad’s cars, so I would like something that I could work on and lightly modify. Maybe something fun to drive. Thanks