Who knows if it’s a common interest. The number of kids who change their major in college is very high so most adults dismiss the career aspirations of 13/14 year olds.
Having any interest, in other words being interesting, increases your chances of being accepted. Picking neuroscience doesn’t seem better to school than picking soccer or Spanish or robotics. They just want engaged and engaging kids.
No it doesn’t ruin your chances, unless your interest came off as disingenuous and trying too hard.