"Hey, I'm really interested in your experience teaching kids how to create GUIs using tkinter. Could I ask you about that over coffee?" If there's a persistent misunderstanding that this is a romantic conversation, you just gotta leave it -- nothing else to do.
You're missing the point. The horrible outcome is that she will forever hold the irrational concern that you're hitting on her. It will colour everything you say or do.
The parent poster's point is that you really can't let that bother you, and that in situations like these a thicker skin for awkwardness pared with straightforward but polite communication will serve you better in the long run.
I care when a woman takes a totally innocuous statement or question the wrong way and thinks to her self "That guy is creepy."
I care when she tells her friends "stay away from that guy, he's a creep."
I care when she gets promoted and becomes my boss and thinks "that guys a creep."
Your best move is to play the game with both hands above the table, not to avoid playing the game at all.
Here's a suggestion for what to say: "Sounds like there's some sort of misunderstanding. I'm not interested in you as anything more than a coworker. We're on the same team and I need to know how to work with you. If you don't want coffee how about we just chat sometime in a meeting room?"
If they're still being weird about it, then it's probably worth discussing with your manager because that other person is probably generally difficult to work with. Also to cover your own ass from the specter of future sexual harassment issues if that's what you're worried about.
If you're just worried about the other person making it weird... I don't mean to dismiss the concern, but there are plenty of weird people out there, and it's unimportant in the grand scheme of things.
In my experience, you have two real options:
1. Add no new information
2. Add new information as unambiguously as possible
I've personally found that dealing with the matter up front and letting the issue burn itself out is the best long term approach to keeping your own sanity.
There's a technique to the second one for making sure your bases are covered professionally since you're in potentially risky territory. Part of it is reporting what's happening to your manager and HR (paper trail). The second part is saying something like "Look, I'm not interested in you, never was. You're not even my friend. You're my co-worker, and we're going to hang out with co-workers. Are you okay with that?"
This can swing both ways of course. I've had situations where colleagues were interested in me, and got nasty when I made sure they knew it was professional coffee.
The correct response for that would be.. "Don't worry, you're not my type."