Welcome!
You will propably meet a lot of "oldschool" players - the last MechWarriorgames are fairly old, so people still playing them (or knowing them) will be way older than you - and playing the game for a really long time.
However, this has also the advantage that you wont be the only new player, so don't be intimidated!
If you really want to put your mind into a game, MechWarrior is the perfect choice. There is a lot more than just a few games - tons of books, a tabletop and pen&paper rpg and more.
You do not need to know all this stuff, but is really nice to have it: You wont get bored with the Battletech-universe.
Most games have little background to offer. Some have a well told story, but you can rarely access it by other means than the game(s).
This is not true for MechWarrior.
The most important thing is: MechWarrior is a GREAT game. It has a great story, a somewhat unique gameplay, really awesome moments and, of you look at this site, it will have totally insane, awe-inspiring, mind boggling graphics and multiplayer very soon!
Oh, try to get some of the older MechWarrior games (MW 4 -Mercenaries). If you do not find a legal copy, try some torrents (of course, only if you are from a country where this is not illegal

) or perhaps some game magazines.
While the controls and some gamemechanics may be different, it will give you a feeling for mech fighting, which is different from most other games.