Christian,
Insurance varies from state to state. You would need to contact an insurance broker in your area to get an exact quote.
There are many factors that go into ins rates, such as your driving history, credit score, etc.. And since you're a new driver at age 16, you may be better off getting on your parents policy. I think getting added to a parents plan as a rider may be your best and only choice, which means your parents take the brunt of your liability, but balance it with their credit & driving history.
Regardless, just because the car is 4 or 5 years old, it's not the car the insurance company is worried about, it's you! Therefor it will have little bearing on the quote you receive.
The largest amount on your insurance will be collision. This is the amount paid out in the event you cause an accident.
The cost is adjustable by the amount of deductible (risk) you take. I carry a $500 deductible, but I have a great driving history.
A $1000 or $2000 deductible will lower the over all cost of the collision, but not by much. This means, if you have an accident you have to pay out the deductible before the insurance kicks in. This could make up 60% of your premium.
The second highest cost on your insurance quote is going to be personal liability & property damage (per person/per accident/property damage), which for you will be HIGH. This could make up at least another 30% of your premium.
All said and done, it wouldn't be surprised if your annual bill ranged between $4500 - $6000, depending on the state you live in. I can only go by here in NH. But if it was MA, it would be a lot higher.
Perhaps your parents will be in the market for a Mustang and occasionally let you drive it while it's registered & insured under their name and you are added as a rider to their policy.
Good luck!