I was probably 17-ish when I got into them. You sound like a decent kid with a good head on your shoulders and a good moral compass, so I'd think you're alright, especially since you seem more interested in the craftsmanship side of things. Honestly though the best judge of your headspace and what you can handle is going to be you.

Just liking gory, morbid, or dark things doesn't mean there's anything wrong with you or you should feel ashamed. It may be something not many people are into or get, but everyone is their own individual. 99% of the people who like this sort of stuff are chill, friendly, good-hearted people who literally wouldn't hurt a fly, and the bad 1% didn't get turned that way by the movies they watch. It's often a cathartic experience for many. Either way, it's a big world and a short life, so like what you like, and explore what you can, and don't be afraid to make your own path.