Whether or not it was the only possible outcome is a question of determinism, which at the quantum level looks like it should be answered with no. That doesn't mean, however, that the outcome is random; it rather depends strongly on the sum of all of the life experiences that have influenced your brain's wiring, all the way since the second trimester of your mother's pregnancy. In that sense, your decisions are uniquely yours.
Whether or not that was actually "you" is a different question, but since "you" don't actually exist as an independent agent (despite your feelings to the contrary), it's a moot point to discuss.
You may be interested in the experiments on volition by the late Benjamin Libet (https://en.wikipedia.org/wiki/Benjamin_Libet).