Yes it's long. An effective gamer would play it in 50-60 hours though. Depends a little if you played Demon's Souls or not or if you "cheat" by reading guides on the internet. For me it took 100 hours to play it through and beat it once (I spent a lot of time farming metals ), but I'm the slow type in all games.

It has some but very few repeating sections yes, and it doesn't bother you one bit. It all makes sense.

Yeah i'm basically a noob at Dark Souls and don't have a clue on what's going on not to mention i'm the slow moving type of gamer. Funnily enough i've only died twice to enemies (due to going the way you shouldn't)....the rest of my 6 deaths have been because my guy will either lunge 10 feet at an enemy and fall off the side of a walkway or I accidently press B whilst in the menus which results with me jumping backwards off a cliff. I hate the games Playstation like controls and menus  If you go the right way the game is quite easy actually (so far at least)

What do you mean by "farming metals"?

Metals you need to upgrade weapons and armor. Titanite shards, Green titanite, Blue titanite and so on. The common metals you can find in shops and drop often from lower mobs but to get enough of some rare metals (like Twinkling titanite) you need to slay a certain type of enemy dozens of times for one metal shard to drop.