What are the basic things I need to know about cars?

I'm a junior in high school and I decided to take an auto shop class because I feel like knowing these things will really help me out later on. Anyways my class started on Monday and I found out that everyone there knows almost everything there's to know and they are just taking the class because they like it. I feel really embarrassed because I literally don't know a thing about cars. I guess what I'm asking is can someone help me get started with some of the basics like what cars are good and reliable and such things as parts. The only thing I have learned so far is that everyone in my school hates Hondas haha.

Transmission fluid turned brown after 10k miles?

I have a 2001 Honda Prelude auto and I was wondering how come my transmission fluid turned brown only after driving it for about 10k miles.
The car currently has 84k miles on it and I'm hoping the tranny isn't going bad.

What happens if you drive a car in second gear at high speed for quite some distance?

I have a new Honda with little less than 1200 miles on it. Today while driving the car I put the gear in S (2) and drove at speed of 50+ mph for around 6-7 miles.
I felt something off about the car as the RPM was between 3500 to 4000 r/min while usually it is between 1500 to 2000 r/min. Also the engine sound was not it usual quite sound that comes - I thought because of the cold weather maybe it was sounding louder.
It was after stopping at a couple of red lights that I noticed that gear was at S(2)
I'm quite paranoid about my car and mode of transportation.
Could someone let me know what are the effects of my driving?

I'm obsessed with BMW and I want one a the age of 18? Advice?

So, I'm an 18 year old guy, and after riding with my cousin to his auto shop in his BMWs, because he had multiple cars from BMW, I developed an obsession. I'm looking for a first car, and despite what I choose, even if it is another German car, I just don't feel the same with any other car.

I'm thinking of getting an older model 3 series Maybe a 1998 or something like that. Any car as long as its a BMW. My dad drives a Corolla, and I'm bored of them because he has been driving Corolla like 5 years old.

Any advice? My cousin even recommends I get a BMW because of their reliability. I asked him what car he recommends for me as a first car, and he said BMW. Now I expected him to say Honda or Toyota, and he is a highly experienced certified mechanic, so I thought he was going to say Toyota or Honda. He said that BMW has been very reliable for him and has taken care of him. Any advice? BMW is a little more expensive to buy, but for any repairs my cousin is a mechanic so he can help me out. But seriously, how to get rid of this obsession? I don't like anther car!

Why is car insurance so expensive for me?

I'm eighteen, i drive very well, never been in a wreck. No tickets. I've been driving since i was fifteen. I want to finance a 2015 mustang from the dealership and got a auto insurance quote from geico. They gave me a quote for 600$ a month. 600$ a month. SIX, Hundred. I find that outrageously ridiculous and am wondering how to get around this money pit. Even when i drove a old honda my insurance was 180 a month. That is such a waste! And so unreasonable! Any way around it? Any logical explanation?