You actually just made my point for me. You had an immediate reaction, that wasn't a choice.
In order for it to have been a choice you made, it would have taken time for you to arrive at a decision.
You didn't need time because you already knew that you could not be attracted to the same sex.
There's a second part to the debunking of the "homosexuality is a choice" myth.
If homosexuality is a choice, then it is a choice that you can make or unmake at any time during your lifetime. So then, you could actually make the choice to be a homosexual right now.
Try it...try deciding that you are now attracted to someone with similar rather than dissimilar gear from yours.
Thank God you ain't doing science. I bet would have made the same quick decision if you had asked him to rob a liquor store.
The choice to be a homosexual isn't an instantaneous decision. It is a PROCESSS arrived at thought by thought and eventually action by action.
Most heterosexuals if they so decided, could eventually become homosexual by the same PROCESS.