Hey man
I'm kind of in a similar camp, been dating someone I thought I was not really attracted to at first.
No sex yet, but I'm having similar feelings like you describe, I like her but I'm not sure, and yet I keep moving forward, so I'm starting to let myself believe I really do like her but I'm having "intimacy calibration" issues from the intensity of having previously dated a BPD.
it's more like I'm at a distance and always have been.
I just told her I need time, that I might be "seemingly cold" while I process things, that its not a rejection. She understood, she's giving me space. it's quite comfortable, I feel at ease, I know she likes me a lot, I'm still not sure, and yet we're both ok with it.
Last time (BPD gf) was pretty much the opposite. at least I'm being open and honest, if things don't work out then so be it, and if they do, only time will tell I guess.
Things happen quicker than I can mature though
Don't feel bad or be afraid to press the brakes, she'll understand. And if she doesn't, then maybe it really wasn't quite right, what do you think?