I'm not surprised if you find that unconvincing, it's a personal thing and pretty context-specific.

I could probably work up some context specific thing too. I largely had the first kiss in mind. I don't think it's a winner for that.

they're likely to spend a lot of the time thinking about when/whether you're going to push past where they're comfortable,

Part of going slow is feeling if they're relaxed and comfortable. If I'm relaxed. If they're uncomfortable, it's time to back off.