Sorry that you are feeling shameful ((do I exist)).
I can understand that you are struggling with memories held deeply in your psyche. The emotions connected to your memories may be very dark and shameful ~ they are valid emotions to (unfortunately) suffer from.
I don't agree that you should feel self-hatred and shameful for things done at such a young age. You were young. Physical pleasure does occur throughout our lives. Caregivers usually gently lead us through understanding human bodies ~ along with what is and isn't socially appropriate. Sometimes, our caregivers avoid seeing or talking about sexuality. We end up learning comfort levels later than we should (or could). This often results in feelings of guilt and self-hatred.
Understanding that your experiences do not have to lead to self-hatred; it does take time to develop that level of understanding. It takes more time to accept the past and "forgive" yourself for what you feel that you did wrong as you were growing up. It isn't an overnight process. But it is one to work towards.
Please do get therapuetic help. Work through your memories with a professional, so they can give their input. An unbiased person sharing their perspective can help you see that your emotions and the memories don't quite match. You then work towards gaining a better understanding of yourself, and allow yourself to forgive and let go of the self-hate held onto so tightly.
Welcome to P.C. ~ gentle hugs to you!