First OB Appt. did not go as planned. Help!

Hi all -

So I had my first OB appointment today, 8w 6d, and it went really well! Well, until I noticed that my coworker was in the lobby and said hi to my husband and I. (The clinic is a women’s clinic that only staffs OB/GYN so it would be strange that my husband would be there except for a pregnancy) I wasn’t planning to announce to coworkers until about the 12w mark, but now I’m not sure if I address it with them tomorrow or if I act like I never saw them. What would you ladies do? I have a good relationship with this coworker, I am just really hesitant to share as I don’t want something to happen before I announce to the rest of the staff. However, while well intentioned, gossip seems to spread around my office like wildfire. Any thoughts or ideas on how to handle this??