Talking about trauma can be nerve-wracking. You might be afraid that others won't understand you, won't believe you, or that you won't be able to tell your story properly. It is important to know that you always decide what you share, with whom, and at what pace. You never have to go into detail if that doesn't feel right (yet).
Still, it can be helpful to share something after all, especially with people who are close to you. It gives them context, allowing them to better understand and support you. For this, it is not necessary that they know your whole story; often a small piece of explanation is already enough to make clear why you sometimes react the way you do.
You can identify what is important to you and what you would like others to know, so they can take you into account. It often helps to give examples from your daily life: for example, that you prefer not to be touched, are easily startled by noises, or find it difficult to travel by public transport. You can also talk about that without going deeply into your experiences, if you do not want to (yet). A sentence like: ‘I have experienced something unpleasant which makes me startle more easily sometimes’ can clear up a lot and give you more space.
Sometimes it can also be nice to have someone read or watch something that puts your experience into words well, such as an article or a video. That way you don't have to explain everything yourself and you can talk about it together afterwards.