Can I offer Sadaqah for a kind sister without knowing her name?

Assalamu alaikum everyone! I was at a shop looking to buy sauce, but it was pretty pricey, so I decided to check another place for a better deal. As I was leaving, another Muslim sister approached me and handed me the sauce-she said she’d bought it for me. I tried to say no and offered to pay her back, but she insisted, saying it was a gift. Her generosity really touched my heart, and I want to repay her kindness by giving Sadaqah on her behalf. The thing is, I don’t know her name and we only spoke briefly. Would the Sadaqah still count if I do it for her without her name? Jazakum Allahu khairan for any advice!