I think this is astute. To OP, it may feel like gaslighting because they only see one side of the coin. Viewing it from her point of view, if she’s been with violent people before it makes sense that she would be nervous of it happening again.

OP, it might be time for a good talk with her, not asking her directly, but reassuring her that she doesn’t have to worry about you becoming violent. That you’ll prove to her that that isn’t who you are. You don’t need to know what happened in her past, but your actions will speak loudly.

Communication is key in relationships, and helping her here will build a strong foundation. If you’d like I don’t think it’d hurt to explain that you felt shocked by her response, but that you hope that your response in talking will help pave the way for future communication.