If you haven't had Felicity within your last 16 villager list - when you visited Felicity, was she in boxes in her home? The one time that I adopted a villager from another town, he was in boxes, so said that he was in a rush to decide. I know that when you try to adopt villagers from your town's own campsite, they may take multiple attempts to talk to them before they ask if they should move in. A friend needed to use her mayor and her second villager to convince Zell to move in. It might be worth trying a second visit to Felicity.
Other question: was Felicity visiting another town's campsite? I recently learned that you can't poach characters from other towns' campsites.