I was raped when i was ten years old. i am 25 years. i have no sexual sensation in my whole vaginal area. why is that?

Likely a deep issue: If you have worked through some of the issues that come with this experience you are on a good path. You may want to continue your therapy & explore this facet of your sensitivities.You likely preserve the hot/cold/pain/localizing sensations that are wired in. Yet your brain must permit sensations of pleasure for you to appreciate them. Allowing them to turn on may take specific work.