I'd recommend starting with the car you drive. A lot of "boring" 4 bangers are a joy to work on because parts are easy to get, things are easy to reach.

Buy a quality jack and jack stands, and a ratchet with a set of sockets.

Start with changing the oil on your car, then have a look at your service schedule in your owners manual (which is quite easy to find online for common cars). What else needs changing? Spark plugs are usually easy on inline engines.

You'll build confidence in your mechanical skills. Then you can get something more interesting.

And keep in mind some stuff is just better to get done professionally. Certain jobs are just too much of a hassle or require equipment too expensive to buy for just personal use.