I was the proverbial "geek" all through school until I discovered college. It was there that I found my niche. I could finally "own" my geekdom, and be encouraged to do so.
I continue to be a geek among other things. I have always been a writer, so the Internet is one of the most amazing outlets I have found. I can write whatever I want (within reason), and people will read it, and let me know if it is good or bad or neither.
I learned to "own" what is good about me when I was diagnosed with Manic Depressive illness. It took a while, but after the long initial shock, I realized that being a geek and a writer and bipolar did not preclude me from being a good person who is truly compassionate, humanitarian, and decent to people who have not necessarily been decent to me. It was the acceptance of the diagnosis that, I think, really made me realize how important it is to identify the good things about yourself, accept them, and "own" them as if they were yours and yours exclusively. If you do not, the illness will literally drive you "nuts" although some of the most amazing people I have ever met have been bipolar as well. It is a disease that for some reason fosters the need for creativity.
I learned to "own" myself about 7 years ago, and it is a lot easier to weather the highs and lows knowing that there are good things about me that I can turn to if necessary.