If you want to use the term Demisexual, if having a word for how you feel helps, then so be it. You seem to fit the bill. In my opinion, you just have a conservative view of sex. No more no less. I think people analyze things way too much.
It is unfortunate you had those experiences in high school. Thankfully, adulthood should bring better interactions for you.
Are you a member of a church? I would think that would be a great place to meet someone like minded. Otherwise, it is enough to simply say to people that you have to take it very very slow and establish an emotional connection before a physical one.
Good Luck.