What should i charge???

*Update: I panicked and told them I'd charge $30. They responded they are willing to pay me $100. Of course I accepted this. But now I'm worried this is a scam or they are truly that kind. How should I deal with online payments? How do I not get screwed over?

This is my first commission and I dont know what's normal. Below is the commission details. I've seen anywhere from $20- $200. Please no one respond with what do u think its worth because that's the point. I have no freaking idea. Ahhhh. I don't want to blow my first commission.

Medium: Digital Style: Hyper realistic Dimension: A3 Deadline: 3weeks Purpose: Gift *Provided subject &pose *Natural scene