There are a lot of comics to read out there and it is impossible for me right now to read them and get up to date with all of that, but I'm interested in Civil War and I never read before a single comic in my whole life.
I found a complete guide to Civil War but before I start it, I wanted to know if it's worth reading without having read any other comics in the past.
Largely speaking, yes.
First off, we need to clear something up: Captain America: Civil War doesn't exist quite like that in the comics. The Civil War storyline is a giant crossover event made up of one core comic series, with ancillary stories across multiple (and many) other books.
If you want to read the bare minimum storyline for Civil War, you must read the Civil War books. The story crossed over into Captain America's own book, but it is "extra" story.
The 90+ issues which make up the crossover event outside of the main Civil War book are within books like the Avengers, Wolverine, Spider-Man, Iron Man, Captain America, Black Panther, et alia.
By and large, the story is fairly self-contained. You can read it and get a general understanding of what's going on even if it's dealing with characters you're not familiar with (there were a few even I wasn't).
So you can, but should you?
Not really. While the main book is largely self-contained, the character development and explanations for their motivations are all in the crossover books. Reading only the main Civil War books is like reading the wikipedia entries.
Do you really need to read all 100+ books?
No, no you don't. Generally speaking, you can skip most of the titles of characters which don't seem interesting to you, but the Captain America, Spider-Man, and Iron-Man books are pretty essential to the main storyline and plot/character development.
tl;dr: Yes, Civil War is as good a starting point as any. However, you might want to pick up some of the prior "introductory" material to bring you up to speed. In particular, I suspect you'll want to read the New Avengers and maybe Amazing Spider-Man issues that immediately pre-date Civil War. (These issues will have "Road to Civil War" printed across the top.
Most of the recent Marvel publication history has been centered around crossover events. There are a few such events that are considered major turning points in the Marvel universe, where things change dramatically. Those are often good places for new readers to pick up and start reading, since they introduce a lot of the plot elements that show up later.
Typically, new readers are directed towards Avengers Disassembled as a starting point, but Civil War is also a reasonable choice.
A complete guide to the entire Civil War storyline can be found here; the "Marvel Unlimited" reading order will give you an issue-by-issue breakdown of what to read, in what order.
Note that it's a lot of stuff to read, because Civil War was a huge cross-over, I believe the biggest crossover event ever. If all you're interested in is getting yourself familiar with what's going to happen in the upcoming movie, I'm going to guess you should focus on these titles:
In particular, I don't think skipping the material from the X-Men titles will confuse you; those are primarily a separate storyline that just happens in parallel with the Civil War one. (The Fantastic Four bits I'm not as clear on, because Reed Richards is a pretty significant player in much of the crossover material, but I don't think anything of broader significance happens in them). Basically, if you're a fan of some character or another, read their story, and you'll find out where they stood on the Civil War topic.
Buy a few graphic novels (Civil War is a good start) Peter (Spider-man) is always angsty. Steve (Cap) believes he's always doings what's best. Tony Stark is a bit of an arsehole; at times, just head to your local comic shop and drop 20 bucks on some old .50c sleeves from '85 - '95 and you'll be good to go.
