I went to BT as basically...my very first raid. I'd been to Kara a couple of times, but neither were successful, and I spent both of them about half the time lying on the floor, watching the fight dead, lol.
I went to BT with similar stats as yours, with a frost build similar to the one mgjr linked. If I am allowed to do it over, I'll take a full 61 points in frost. (Don't look at my build right now, it needs tweaking, but there are some nice onces in the Improved Frostbolt thread). I just have the evocation glyph so far (well, and the penguin, which doesn't really affect anything), but I'm going to get the mana gem one today. I didn't have any mana problems, though, with the regular gem. I had some pots, maybe chugged one, but I don't remember.
We got to Mother and though we got her down, it was really horrid, because there were only a couple of people who had SR gear (I did not, as I didn't think there was any way in hell I'd be allowed to go, so I thought I had another week to work on the SR gear, thus I died every time). Anyway, I worked my *** off to get the SR gear for the next try, and though not all of us had SR gear, we still got Mother down much more quickly and tried the Council. The point is, though, that I lived through the fight with Mother because I did have the SR gear, so work on that as much as you can. (I had 238 SR, but just get as much as you can, that **** is expensive to have crafted.)
Our guild is kind of up in the air about raiding and etc right now, so we still have not seen the Council down, but I hope to before the expansion, just so I can SEE Illidan. :)
Anyway, my advice as a brand new newbie raider is to become as agile as you can in your play style. I have spent most of the time up to lvl 70 standing still (with the exception of some PVP), but if you can learn to follow someone's orders while they're calling the shots, stacking when they say, avoiding moving dangers, etc, you'll do fine. It's something I'm working hard on and getting better at.
Also, go to bosskillers.com and read the strats for each boss. I came away from that site feeling a little more confused than when I went, but once the raid was actually happening, I found that I remembered some things from the strats that helped me tremendously.
And if this is your guild's first try, don't be disappointed if you can't get all the way through the first time unless you have a lot of hours to spend on it tonite. You have a lot of people learning a lot of different things, so it takes practice (Bloodboil is FUN!)
Good luck, and have fun! I hope your raid leader is as knowledgable and patient as mine! :) Let us know how it goes. :)
P.S. Get your hit up as much as you can towards cap, and spend some gold on consumables. I'm a superior wizard oil addict (for a little while longer, sigh), and I like the adept's elixir (though something like Flask of Pure Death might be less expensive if you end up dying a lot and are spec'd frost or fire), and buff food.