Study math now! With reverse ageing in the future you could potentially become one of the best in the field. There is time.
Throw it away, what's left to need
When you’ve got infinity
So much out there left to find
We'll do that some other time
Are they ? As far as I know, neurons last more or less from before birth to death. There is neurogenesis in the hippocampus but it doesn't replace existing neurons, and the new cells themselves last until death.