The thread title and the first post pose two different questions.
What got you interested in Civil War history?
I had a general interest in the military as a child, probably due to my veteran father. Ken Burns Civil War miniseries and TNT's Gettysburg came out at a formative time in my life, and my middle school teacher had Hutsell's CW Battles and CW Strategy (DOS games) on the classroom computer. Then in high school I decided to read Foote's trilogy instead of...well, anything less extensive. It all snowballed.
Alas, my life-changing trip to Gettysburg, Antietam, and other battlefields didn't occur until I was a decade removed from high school, but that plus the sesquicentennial shifted my interest into a higher gear.
As to the other question: "Why do you like the ACW?"
I think this is the more difficult question, at least for me. Many will say ancestors who served (I don't have any) or maybe the collecting aspect (I don't collect anything for myself except knowledge and memories).
In my youth, I think it was mostly the West Virginia aspect (seceding from secession appealed to me) and the involvement of the only famous person - at least that I knew of when I was a child - named Joshua, besides some guy in the Bible who yelled really loud, even though I didn't read much about either West Virginia or Joshua Chamberlain.
As an adult? I think the ACW is in a sweet spot in terms of the size and scope, compared to many other wars throughout history. Being able to visit many of the battlefields is probably part of the appeal.
Perhaps most of all I read a lot of nonfiction and I tend to read widely rather than deeply. We are blessed with a lot of good modern literature about the ACW (I love lighthouses but good books about them are rare). After 15 years of avid reading I'm still finding good books about aspects of battles, generals, and other aspects of the war I've not read about before. My curiosity remains unquenched, unlike some other subjects that have exhausted my interest.
I have over 2000 books on my Goodreads account (Read or To Read). 460 are tagged American Civil War, more than any other category. Among miitary conflicts, WW2 ranks a distant second with 114 books. Even books tagged Florida (the state where I live and about whose history I read both for personal and professional interest) has 255.