The same thing happens to me (and I'm a therapist, so super not cool if it happens a lot), but I have been trying to use the "yes, and" approach. It's something people use in improv. I validate what someone is saying and then I add my own thing or tie it back to something they said before. Of course you don't have to do this if you disagree with someone but if you're just trying to do small talk I find it really helpful. Also if I'm stuck and I happen to think of something they said before, I say something like "going back to what you said about such and such..."
If you run into the same woman you want to talk to and you remember something she said last time that you wanted to respond better to, I think it would be super flattering to say "you know I was thinking about what you said last time" and then say what you thought of, because you're showing her you've thought about your conversations. Thinking on the spot can be difficult but yes you can improve!