Make sure your hosting supports webfinger, otherwise activitypub probably won’t work. I’m on Siteground and they explicitly prevent it. Matthias Pfeferle, who wrote the ActivityPub plugin and now works for Automattic, actually asked them to enable it but they said no. Other hosts might do this as well.
It was a long time ago that I realized that women’s clothing sizing was largely fiction. Trying to buy clothing for a girlfriend or (later) my wife based on the tag of something they already owned was an exercise in futility.