So, you're saying your "Captain" was a babysitter to age 16 and then 9 years later she was given command of a ship? Is that what you are asking?
When I was 25, I was a 2nd Lieutenant in the Army, which is equivalent to an Ensign in the Navy. No one in their right mind would give an Ensign command of a ship at age 25. I know this is [i]just[/i] an RP. The idea of a 25 year old command a ship in today's world, completely baffles me.

The size of your ship would dictate a Lieutenant Commander. To get to that rank, an officer would have to spend at least 12 years in the Navy before that happens, which would put her at 34 years old after four years in some commissioning source (college/university/military academy). The only thing nepotism does for a sailor or soldier is bring down a boat load of flak from subordinate.