No! Looking at the sun once will not make you sensitive to light, so this was in no way your fault! You said that the light sensitivity began at puberty and so I think that it was a new sensory issue that developed as your body changed.
I have personally discovered that though I have my core sensory issues such as itchy textures and loud noises or crunchy vegetables that look like leaves, I also have some that occur as my body changes. Since I became vegetarian, I can no longer stand the smell of meat and since I used Plan B and it messed up my hormones, my sensitivities to certain smells has increased threefold and if a place smells weird I am no longer able to cope through it; I now have to leave the place entirely just as I have usually had to do if a place is too loud...
So do not worry, just because you have a memory that appears to correlate with a sensory issue or a compulsion, it does not mean there is not anything you did to cause it! I am not exactly sure why our intense aversions develop, however, they usually occur naturally with extreme adoption, just as our positive fixations do. .
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"All by myself I am a huge camellia
glowing and coming and going, flush on flush."
-Sylvia Plath, Fever 103