Welcome from another newbie. There's still a lot of SK books which I have yet to read but as of yesterday, I'm 100 pages into "IT" and it's great - very creepy and utterly engrossing. Keep having to remind myself to put it down and eat! Whatever you choose, enjoy....
lol yes grown up books. i'm 26 almost 27, but i haven't really read anything since HP. I read about 70% of The Godfather, but just couldn't make myself finish it because I've watched the movie roughly 6000 times in my life (best movie ever) and the differences between the book and movie were non existent, to the point of the movie being a line for line copy of the book. everything i've read since has either been a biography, or some sort of non fiction book. i just needed some new adult fiction in my life.
I don't think that there is a wrong way to go. Well, I wouldn't read the DT books out of order.
Did you know that Stephen King is/was a pretty big fan of Harry Potter? Me too!
Have fun. King's stories are great. Enjoy the journey!