I'm all for spiritual connection but your mom seems to be delusional. The way she told you that you are a Nephilim seems to be rather in a worried paranoid way. Spiritual delusions are common. I say this with concern due to my mom dealing with the same thing and her delusions were focused on me. From medical issues I didn't have to believing I was possessed to believing I was an evil spirit to believing I was an animal that needed to be caged.
If you can, get her help. It may seem cool now but it's not something to be taken lightly.