Pecco, you can do it! From one newbie to another, I know, because I've been there myself. While I'm a newbie to this forum, I'm not a youngster age wise. Many year ago, I faced the same situation as you, but in the film days. I just jumped in there and it went well as I did weddings (and other things) as a part time business for 25 years or so. I still do a few things like high school reunions, etc...but no weddings, they're too demanding mentally and physically now. I did one wedding after going digital and that was a case where a young girl in our church needed a photographer for cheap (his dad was very ill, etc) and we did it for a wedding present, but I told her it was my first wedding using digital equipment and it came out pretty well. I did 200- 300 weddings over the years with film. I say all this just to let you know where I'm coming from.
To be ready in a year, decide on the equipment, buy it soon and practice...make sure you have the techniques down that you plan to use and practice with those at any type event that you can shoot...church functions, company parties, birthday parties, etc. Volunteer to do them, so you get the practice doing things under pressure, because the pressure of getting a wedding right can be tremendous as others have pointed out. If you can talk another wedding photographer into letting you go along with them, that's a real bonus!! To me the trickiest part of shooting a wedding (exposure and color balance wise) might be when combining flash with ambient/other light. Also, you must use some flash technique/equipment to keep it from being a head on straight flash. Get the flash up, use a diffuser, multiple flashes, etc. it doesn't have to be really expensive or complicated, but study others flash techniques and their results and decide what you're going to do. Do you know how to balance daylight/flash exposures in case you shoot some outside? Not just color balance, but the exposure itself.
Read, read, read...besides books, I'm sure there must be some online forums that specialize in wedding photography as well as magazines, etc.
There is a lot to deal with at weddings besides the equipment. BTW, you MUST have backups for everything.....at least two of everything....bodies do break, flashes quit working, batteries die, etc! But the people problems can be killers...SOMEBODY will be late! There will be pressure to hurry up with the pictures so they can get to the party, etc. When are you going to shoot the pictures, before or after the wedding or both? Does the bride want the groom to see her before the wedding? Do you and the bride want some traditional family group shots and wedding party shots or all "candids"? How do you align/pose groups and individuals? Who is going to make sure the dresses are straight and the flowers held properly, etc...here's where an assistant can really be helpful.
In a way, digital is better than film days...at least you can get an idea of what you shot...exposure, sharpness, etc but on the other hand, when I was shooting film, I did my part as best I could and the professional labs I used did the part you now have to do on the computer.....color balance, exposure correction (yep, I missed a few and they saved me most of the time). Of course they did all the printing and I delivered proofs, then had the enlargements printed of the bride's selections. Are you going to deliver digital files right out of the camera or are you going to have prints made of her selections or a book or ?? Working on each digital file takes a good bit of time.
What does the bride expect from you? Does she know you've never shot a wedding, if not, tell her! If you're doing this for a present (no cost), that's great, but make sure she knows what you're giving her...files, prints, book, album, whatever. if you're charging something (you can get more work than you can stand if you work for free) give her a price that's considerably lower than the going rate. That helps you get started and gives her something in return for the risk she's taking since you have no wedding experience. We all have to do our first wedding sometime (if you're going to ever do them)!
Back to the equipment for a minute...I think equipment is too often a hangup, but all the rest of the stuff is probably more important in the long run. A good eye for a picture, timing, ability to deal with the people, being organized, being able to handle the post processing/printing, business sense, etc, etc. Sure, you must have adequate and reliable equipment, but you don't have to have top of the line or the latest thing. At a wedding you're going to need a wide angle lens, esp with the crop sensor and up through the "normal" and mid telephoto (100 - 135mm) range for sure! How long a lens do you really need....I don't know for sure. In my day not very much, but I don't know what all type shots are in vogue today...
Go over the whole plan with the bride WELL in advance of the wedding.....does she have special shots she really wants? Can you do them? Go to the church or location of the wedding in advance.... AT LEAST attend the rehearsal. Tell the wedding party and family where you expect them to be and when....let them know how important it is to be there and on time! Make sure who all the bride wants in her pictures and make sure they get the word. Nothing kills you time wise much worse than a wedding party member being late or you have the bride's family all lined up for a big group shot and someone says, oh we need Uncle Joe in this picture and he's over at the reception hall, etc!
Be prepared for uncomfortable situations....family groups with divorces/mixed family groupings or family issues that cause people to be uncomfortable, etc. Say you call out for the groom's family to come up and then you realize his dad is divorced from his mom and he's remarried to a cute young thing about 20 years younger than his mom and they DON' T want to be in the same picture together (or the same state for that matter).
I'm getting numb from writing...to much thinking at my age...LOL!
Maybe I've given you some things to think about...though not all directly related to photography and equipment. If you have questions, fire back and I'll see if I can answer.
Best of luck and preparation to you!!