but since it's that easy...
I had a good friend in middle school who had a girlfriend here and there. When he was 15, he told us he was gay. Over the next few years and countless discussions with him, he said he always knew he was gay but made himself try girls. Said it made him miserable. He only found out how to be happy once he went with his true feelings. I guess you could say he made the choice to be himself (gay) but that's not really what we're discussing here.
But unlike you, I haven't based my entire opinion solely on his testimony. In fact, I told him that I believed that you aren't just born gay. But over time, I've seen enough to change my mind.