I've been driving for 2 years now. Like you, I have the car fever. When I was 16, I knew a bit about cars (general principle of how they work, how to check fluids, etc.). I had read the owners manual of all of our cars cover to cover. But when I got my car I decided to learn all that I could about it and other cars. I started out by reading my owners manual, then graduated to the internet. If I had any question at all, I would google it (still do). For example, "how does traction control work" "87 vs 91 octane" "best 5w30" "best allseason tires". Don't be afraid to ask the internet questions. For example I'll end up on a Mercedes forum reading about adaptive cruise control, or a Geo Metro forum reading about their average MPG.
Youtube is also a great resource. There are videos on tons of automotive topics. In this one, a guy tears down an engine and explains its different parts and their functions.
https://www.youtube.com/watch?v=saPGX-1qC4M&t=464s
This one is an engine running with a clear cylinder head. You can see the whole cycle.
https://www.youtube.com/channel/UCFH4dWqQQOYkyJZUGT4q5pg
If I look at the engine in my Buick, for example, I can learn a lot. It is referred to as the "3800". It is a 3.8 liter (if all the pistons were at the bottom of their stroke, you could pour in 3.8 liters of water) V6 (there are six cylinders, arranged in a v-patttern, in two banks of three. Being a 90 degree V6, the cylinder banks are offset at an angle of, well, 90 degrees. GM rated this engine at 200 horsepower at 5,200 RPM. That means that when I floor my engine and let it reach redline, it makes 200 HP. This is less important than torque: it's also rated at 230 ft-lbs at 4000 RPM (revolutions per minute= how many times the crankshaft revolves in a minute) Having adequate torque is what allows a car to merge onto a freeway or spin the tires. It's arguably a more important metric to measure a car's performance. Generally, the higher the torque, the more powerful the engine will feel. That's why trucks, often used to tow, will have much more torque. For example, a 5.3 Chevy has over 350 ft-lbs of torque.
But when talking about speed, the two most important things are 1/4 mile time (obvious, and it is listed at a given speed- the speed at which the car crosses the 1/4 mile line) and 0-60 time (how many seconds it takes). Those are how you would compare two cars and see which would win.
You mentioned the use of the same engines in different cars. A 3.5 liter V6 has been used by many automakers (Honda, Toyota, Ford, GM, to name a few) but they are all different. Toyota's 3.5 isn't related to Honda's. And Toyota may use it in the Sienna, Highlander, Avalon, etc, with a few small changes.
So I guess that I'll leave you with the advice that you should be open to learning new things and you'll find that you become knowledgable over time. On the left bar of this forum there is a recent topic list. click into them, read them, and try and learn something.