I think what happens next is up to you. If you want to talk about the traumatic incident again at your next session, you can. You can tell her you blurted it out so she would know but you want to work on something else. You can tell her you're not sure how you feel about having shared, and talk about what sharing it felt/feels like.

Think about what you want or need, and you can decide what happens. Good job sharing! Getting it out the first time can be so difficult.