So if there were a 20 year old who practiced a religion she be insane and out of touch with reality? She would be unable to reconcile her faith so she couldn't be a scientist or engineer because she thinks irrationally?
That depends on what you mean by "practice religion". If you mean for example, believe in an afterlife as a fabric softener of the mind because dealing with the reality of death is too frightening, then yes, I would call that losing touch with reality.
Just found some books she is reading and they are all about Islam. I have mentioned before that her best friend is a black Muslim girl. My daughter is in 8th grade. The question is, should I intervene?
That depends on what you mean by intervene. If by intervene you mean forbid it, that will do 2 things I think you don't want. 1) it will drive her away from you, and 2) it will drive her right into what you attempt to forbid.
If by intervene you mean spend an hour a day learning science together with your daughter that would be time well spent. 1) It will bring you both closer together, 2) It will be less time spent watching "reality" *gag* tv, or some other mindless entertainment or worse, radical Islamic propaganda on the internet. Not saying either of you do that now, just saying quality time spent learning > *.
You can watch YouTube videos on science together. You can tell her you adhere to the tenets of science for example "Extraordinary claims require extraordinary evidence" and explain to her why that is important. You do know why don't you? If not just ask, some of us will be glad to help. You can talk about the scientific method together. You can talk about all of the contributions science has made to improve people's lives.
Here's the right way to do it: First, find out what she's interested in the most. This may change from one day to the next so ask often. Ask her what she's learned recently that she finds interesting. Don't lead the conversation at first. Let her lead to find out what she wants to talk about. Then talk about whatever subject she brings up and work the "magic" of science and how it applies to her interests into it slowly. If she says "I don't know" or "whatever" or some other such favorite phrases of empty minds* typical of teenagers, then you need to be prepared with something you found interesting so do a little homework beforehand on some interesting current event in science.
*Note: By empty minds I don't mean stupid, but literally empty and ready to learn. Quite the opposite of stupid in fact. The power and potential of an empty mind is not to be underestimated. Sometimes people get stuck in their ways because they are not willing to take on any contradicting views to what they think they already know. It's easier to learn something new when some erroneous information isn't in the way blocking new learning. A famous author once said "The trouble with the world today is not that people know so little, but that they know so many things that are just not so."