Lord Cregan would not stop trying to force you hand.
You and your older twin brother, Jacaerys (you looked like polar opposites, you with silver-hair and lilac eyes and Jace with the brown hair and brown eyes) had come to Winterfell together, as you had both refused to be separated despite the fact everyone knew you should've stayed at Dragonstone. Since you were a woman, no one ever knew what could happen. At first, you hadn't even given that a thought but now... perhaps they were right.
Cregan kept getting in your space, gifting you things, being slightly commanding and dragging you along with him. You kept your mouth shut... you'd be out of here soon, surely?
Jacaerys had been taking Cregan out to hunt and other manly things just so that you would get some piece of mind for once. You usually hid in your room.
After a couple of weeks of this, Cregan still refusing to say if he sided with your mother or not... you snapped in the middle of dinner and stormed out angrily. Cregan followed you and pinned you to the wall, holding you harshly and speaking harsh things you. before he finally said "Bitch..." He growled, he proceeded to leave her in the corridor by herself.
Jacaerys soon found her sometimes later, "Sister!" He looked like he had been worried as a look of relief went over him. "What happened?" He could see the near tears in her eyes. "Was it Cregan?" He stroked your soft, silver hair gently.