I know how you feel. I was 40 yo before I told anyone, including my husband, about my childhood abuse which included sexual abuse as well. I am now 60.
I recommend you find a good psychiatrist and take an antidepressant and an antianxiety medication. Propranolol is helpful for the hypervigilance and overactive startle reflex. I also highly recommend EMDR therapy.

Good luck. With treatment, life becomes better.