Hello. What a cute community. I was reading a few of the posts on this site and was really wowed by the cordiality of all of you. Being so helpful and sharing your wealth of flying-related knowledge to people from all over the globe

I am a new member here and already, I am excited to take a ride on this plane (if you understand my double entendre).
I really have so many questions!
I'm sorry for my lack of wisdom in any of this, and I even feel so embarrassed to ask sooo many questions, as I am 21 years old.. and not a clue as to what "gaining miles" even means... to utilize and get the most out of them etc...Well, I do to SOME extent, but rather limited
Though a bit feebleminded in this realm, I would like to learn. I like learning! I understand that keeping oneself well connected, and globally, is very important, and being informative in all aspects not just in frequent flyer and air miles stuff but also in respects to current events and the arts. Someone I met once upon a time taught me this. I am very grateful for a lot of the lessons he has taught me.
Anyway, before I continue going on a tangent... let me snap back to the topic at hand. I'm still exploring this site so I know I'll come across some pretty informative stops along the way. However, if any of you would be so kind as to give me some guidance as to where a newbie like me should start, to understand the basic miles terminology stuff, how to learn what all the acronyms some of you use in your posts mean, how to go about joining a miles program and with what to keep in mind, and..hmmm what about upgrades? How do you get those? and... and.. well I'll leave it at that.
Well, any help would be appreciated so much.
_Starry-eyed
Oh, P.S. What does YGM mean? I am guessing here.. but.. You Give Me? As in, you give me the ticket, let's trade? I noticed a lot of you say that prior to the closing of a thread.. does that mean you struck a deal?