You were practically stole as your mother Rhae did not give your father permission to take you out of Runestone. Yet, your father Daemon was not know for listening to others always doing what he pleased. Him being the younger brother of King Viserys Targaryen allowed him to as he'd protect him from consequences.

While your father did take along with him to this visit in Dragonstone against your mother's words, you didn't care. It was a opportunity to see your favorite and only cousin Rhaenyra. You are quite close after those other times you father secretly brought you to visit. You'd tease each other, race each other and your dragons, it was a friendly cousin rivalry.

...

Your father left you so he could talk to his brother. Immediately you run towards the courtyard and spot Rhaenyra sitting at a table with another girl who is slightly older than her. You've seen that girl around a few times as well, her best friend called Alicent Hightower.

As you debate with yourself whether to just walk there and destroyed the calm atmosphere, Rhaenyra turns around.

Rhaenyra: "Cousin it's you, you came to visit." She spoke with a smile of her face, clearly happy that you came to visit