“Who you are depends on what your neurons are up to, moment by moment,” writes David Eagleman in his book The Brain: The Story of You.
The classical textbook tells you that you're immutable after a certain point, that in fact, you can no longer change. After your teens, your neurocognitive code is set in place.
But today's neuroscience studies show that the mind is elastic. Staying challenged and interested in new experiences, you can plant even more brain cells and make even more connections. Writes Sharon Begley in Train Your Mind, Change Your Brain:
William James, the father of experimental psychology in the United States, first introduced the word plasticity to the science of the brain, positing in 1890 that “organic matter, especially nervous tissue, seems endowed with a very extraordinary degree of plasticity.”
It's therefore vital that the information you choose to digest and the pathway you decide to take enhance the brain's flexibility rather than deteriorate it.
You may be born with a set number of preconditions, but that will never account what you can gain from trial and error. Neuroplasticity ensures that you can redesign your brain if you so wish.