The regret of passed opportunities can become a heavy weight. There's always reasons or ideas to not do something in order to reduce stress or placate the mind, but is it always worth it? Probably not. I completely understand where you're coming from. Being assigned books to read results in people being completely matched with what they're capable of reading and what they would like to be reading. I, too, dislike To Kill a Mockingbird for the same reason you do. Regarding your last point, I would definitely recommend doing just that. I hope you enjoy the book.
I've never read To Kill a Mockingbird, but I saw the movie, and frankly I didn't find it particularly remarkable. Could it be that it's just one of those books that had social importance at the time, but isn't really that interesting any more? In Capote, Truman Capote says (about the book) "I just don't see what all the fuss is about." Sure, he was a narcissist, and almost never impressed by anyone else's work, but maybe he was right this time. I started reading Uncle Tom's Cabin a few years back, and even though it's a very simple and short book, I couldn't bring myself to finish it. It was that fucking bad. I can see how it made a big impact with its criticism of slavery while slavery was still in effect, but reading it today, all of that is fairly uninteresting in itself, and all that's left is a book filled with bland characters, and repulsively boring prose.
As a rule of thumb I generally don't watch movies for classic, renowned or otherwise highly acclaimed books if I haven't read the book. there's really no sense in drawing an opinion and conclusion on the book just by watching a movie, which could easily just be a loose interpretation backed by some producers, made for money by a random director a hundred years after the book came out.
That's a fair point, but this particular movie was made in contemporary times and critically acclaimed. The things that bothered me about the movie (boring story, flat characters) are things that could easily apply to the book as well. However, I won't claim to know the book, I was just raising the possibility that it's not that great.