Wanked While Being Watched

When I was 15 I went on a hike along a river and came across a younger girl who apparently lived nearby, I think she was 10 or 11. We talked for a while and then I had to pee so I went behind some bushes but after a minute she followed and saw what I was doing and teased me a little saying I see your willy. Now I am *not* attracted to pre-pubescent girls, I do not want to have sex with them and have never tried to repeat anything like this. But I was turned on by having her watch me, so after I finished peeing my dick got hard in my hands. She kept looking at it from several feet away and asking what I was doing as I started jerking off. She said "that is weird what are you doing" and I just sort of stuttered and stammered and kept stroking and looking at her, her face and her mouth in particular. Then I was shocked that after only a minute I could feel an uncontrollable impulse and felt like a robot out of control, I couldn't do anything but jerk a few more times as I started ejaculating onto the ground, spurt after spurt, she said "ew" or something. I guess I was pent up and hadn't cum for several days so I just needed this very minimal visual stimulation. Again I didn't really want to do anything with her, she just stood there and it happened. I felt bad afterwards but also sometimes thinking about this when I wank off, but I also feel guilty when I do this. I never saw her again, and would probably try harder to avoid anything like this happening again.