Intro to Epic Fantasies/Sci-fis?

I've always been a big fan of fantasy & sci-fi as genres. However, I've always read the more tame stuff and was hoping to delve into epic fantasies & sci-fis more so. I am older but will still read YA books but also will read Adult books as well and am open to suggestions for a good place to start with these.

I think the closest thing I've read to an epic is the Realmbreaker series by Victoria Aveyard but I still haven't finished it.