When I was between the ages of 4-6 years old my half sister who was 5 years older then me touched me in places she shouldn't and did things that kids our ages shouldn't even know exsits at that age but I'm 19yrs old now and its never really come to my attention until she asked me a year or two ago if I remembered what happened when we were little when I would be down visiting for the week and when she mentioned it it's the only thing I can think about now that I was sexually abused its hard to cope with because were some what like friends even though we live with our moms (but have the same dad) but when she asked I didn't want to talk about it so I lied and said no making her think I didn't remember this has been a secret for 13 years and it would explain a lot with my emotional and mental health the way it is so should I tell my mom or just leave it a secret it happened a long time ago and hopefully ill forget it again

Boy that's really a toughie my friend, I think maybe you should try to tell her simply that what happened but in a way she'll understand and that you'll feel comfortable. Just take your time because you have plently of it, but early repressed childhood abuse has been known to cause some SERIOUS mental illness. You need to confront your demons one way or another just make sure you do this in your own personal and safe way.