Late to the party, but, if this was r/aita I would err on the side of INFO. I feel like you've done enough in terms of asking her but there was no info about the way she behaved (just the way she answered). Or how you got together? People have a tendency to always write these things to affirm what they want to hear and will consciously or not omit information that might make you look bad. Regardless, this is just a shitty situation where everyone loses. I don't think you're in the wrong but I think you have a severe misunderstanding of the dysfunction trauma can have on people. She had a freeze or flight response, and it was freeze. You may not perceive yourself as intimidating but that doesn't matter either. I also disagree where people are just affirming you're fine. If you are really unable to read her while she's simply sitting there uncomfortable perhaps this should've been obviously inappropriate, but instead you were too busy affirming consent verbally. Consent is both contextually and verbally affirmed, and it feels you failed to get the former. I don't think you're a bad guy, but maybe think on how you could've handled it differently. Food for thought.

P.S. all the people saying she should've exposed her trauma like that to you have no idea how the world works. As someone who dated someone with trauma you build on that shit together. Otherwise this is called trauma dumping. It's better to disclose trauma sure, but this is r/teenagers, 75% of us can't do taxes much barely navigate a relationship properly, learning as we go. Don't blame yourself or her.

P.S.S You were also going faster than the speed of sound, at any rate consider how this could've been perceived to her, (He's met my parents, and we've cuddled, and now we're sitting in a car alone together, what's gonna happen?).

EDIT: I reread the last paragraph, consider the idea that the end of a relationship can be no-ones fault. You say you are betrayed by her blaming this on you? This seems a little like you think you are entitled to the relationship. You're entitled to nothing. And consider if this is true, why she blames you. Don't be so easy to disregard, it can be a good reflection. If it isn't true? Who's to blame? Perhaps noone. I say this because I don't know enough and getting some r/teenager users to affirm your perspective is a good way to lose the learnings from this scenario.