While it's not the end of the world, I really, really discourage you from playing the games chronologically. Contrary to what other fans have said, the games were not made to be played that way. You'll miss a lot of subtle references and you'll be more enticed and be single minded about the canon rather than what the individual games were trying to achieve at the time.
MGS2 wasn't about Raiden or the Patriots. It was about the Metal Gear fans who are overly eager to swallow anything that popular media fed them, regardless if there are unforeseen consequences to that, and MGS2 shoved that consequences in your face, delivering an experience that is infuriating at first, but bold, sincere, and thought-provoking and ultimately becomes a cautionary tale.
MGS3 wasn't about the beginnings of Naked Snake. It was about Kojima trying to apologize to the fans after the nonsense of MGS2 and gave fans a straight up, back to basics, stealth experience. During E3 2004, the tagline of the game was about the series being at a desperate state to survive and the future of the series relies on this particular game to win back as many fans as possible.
That's the main problem I have with MGSV, I can tolerate anything Kojima throws at me, so long as it has that underlying message that the first 3 MGS games were so good at delivering, both in and out of canon.