I've just finished both of the first season (and all of the third season so far) I've read a lot of the reviews just mentioning the sex, drugs, gore and violence, yes they are there almost all the time there are some positive role models, for example Kit (Evan Peters) in Asylum Wrongly accused of murdering women, had two wives who both died, was wrongly locked away in a mental asylum, almost sent to death, canned, whipped and locked up however even through all that he remained a good person, I'm pretty sure he's the only main character that didn't kill anyone. He took a young woman's 20 lashes as well as his own after the two were found having sex (explicit but not graphic and they loved each other he went on to marry her later so it wasn't just some fling) and even after he had been released and the people he cared about had died he made sure he went back to help the nun whom accused him and whipped him mercilessly, Kit is an extremely good role model and teaches to forgive. I cannot think of a decent role model in season 1 however in season 3 from the 9 episodes I've seen so far Zoe (Tassia Farmiga) seems like a good role model who would put herself in danger to help her friends even though there not always there for her and feels genuine compassion for some characters even when no one else does. It also gives out some positive messages-
Season 1; Stand up for yourself; Be there for the ones you love; Never give up when times are tough.
Season 2; (I found there were quite a lot of strong female characters who stood up for themselves, it really gives off a good message to young girls, they don't need to be have a man to be successful as demonstrated by Lana) Don't let others tell you who you are, only you decide who you are; Don''t ever let a man make you feel worth any less than him; Forgive; Never give up; Don't have sex in an abandoned asylum; You can achieve your dreams if you work hard enough.
Season 3; Stick by your friends; Be loyal to those you care about; Don't be racist (or sexist or homophobic or anything like that, those two weren't shown in AHS but I thought I'd add them anyway); keep an open mind.
Even though it has the good role models and positive messages there is a hell of a lot of language, drinking smoking, some drugs, sex (never graphic but almost always explicit), violence, torture, human experiments, disfigurement, mutilation, self-harm and suicide (in season 1 Violet self-harms and later commits suicide but overdosing on pills, also kind of dreams/imagines slitting her neck to end it all, also Tate admits he used to self-harm but tries to get Violet to stop, also in season 1 a woman shoots her husband then herself, season 2 a man shoots himself leading to a car crash then again in season 3 another person shoot them self), some cannibalism,rape, and then some. In terms of scariness (I am someone who personally can't deal with jump scares or normal horror movies however I cope with these fine, although they sometimes shake me up a little and shock me) There are no jump scares in any of them, and if things do suddenly appear you were expecting it and were meant to be expecting it. All the horror is done in a way I think a lot of horror movies (especially newer ones) disregard, even though they use the shock factor with the gore and violence you get a feeling of genuine horror, they use an extremely good plot with great characters and superb acting so don't rely on cheap theatrics to scare you.
tl;dr? Here's a quick summary of all so far-
SEASON 1: The Murder House- Fairly scary. Not much violence however a lot of sex, the whole storyline is based on an affair and a miscarriage. Ghost/spirits are almost always there, gay sex, kinkiness, rape, and of course murder (via gun, neck snapping, knife, shovel, drowning, some creature in the basement that you never really find out what exactly it is (it's implied to be a baby that was abandoned years ago, pretty sure it is one of the spirits trapped in the house), car hit and run and some other things.
SEASON 2: Asylum- Scariest season by far. Sadistic ex-nazi doctor, evil nuns, aliens, mental patients and (this is what really got me) a killer called Bloody Face who abducts women, skins them alive, makes furniture out of the skin and bones (some of the furniture is seen like a bowl made from what appeared to be a human skull and a lamp with the lampshade made out of human skin), decapitates them and wears their faces as masks. Dead bodies are seen, some rape, a horrible, horrible torture takes place in which a woman's legs are cut off and her skin is burnt and she becomes very disfigured and mutilated, someone's arm is ripped of, people are shot, and murdered in many ways, another hit and run (not graphic again and a lot of remorse is shown)
SEASON 3: Coven- Least scary. Only disturbing thing about it is the way Madame Delphine LaLaurie treats her black slaves and is extremely racist, she also tortures her own daughters when she finds them planning to kill her, acid is thrown over somebody's face (blinding them, witches are burnt at the stake, someone cuts off their own tongue, more murder using knives and sex, gang rape of an intoxicated girl, a Frankenstein type monster is created and some more however no where near as disturbing/scary as the first 2 seasons.
I think it is pretty suitable for mature 14 year old or, if not mature 16/17 but it really all depends on your child, what you know they can handle and if they're going to take some good from it and appreciate that it is actually a great show.
I hope my review helped :)