Well, it does travel through the air. You chatted with her face-to-face and that's often enough to spread it.
This particular virus also lives a long time on surfaces touched by an infected person. Days depending on the type of surface.
There’s research showing that flu like viruses travel well in the air under 6 grams of absolute humidity. Charlotte on April 1 (for example) was 5. SO you’re probably right; just chatting with the woman on the porch.
It’s also possible it was the handling of the groceries. I spray bleach on a paper towel and wipe them all down before putting them away. I soak produce in a pot with water and 1/4 cup of lemon or lime juice.
More than likely transmitted from touching the grocery bags, especially if the other person wasn’t wearing gloves, touched the bags, etc.
And those groceries were touched by both.
“Well, it does travel through the air. You chatted with her face-to-face and that’s often enough to spread it.”
Repeating things said in the media, that they are simply repeating because someone else did, does not make them true. There have been assumptions but no studies have tested or confirmed those assumptions.