On the one hand, you could get the medic cert real quick, and go to school, for the three years or more it would take for the RN, and be able to do it on a liveable wage, or have to go to school while making no money, or maybe for 10 bucks an hour as an EMT if you want flexible hours. It may be that your financial situation will not survive three years of poor compensation.
On the other hand, you can get the degree, be paid well as an RN, challenge the medic cert exam in some states (or just do a quickie mill), and be able to work as a medic (if you still want) and not be owned by the EMS agency. With a degree, you'll always have options.
With only a medic cert, you may intend to go back to school, but what often happens is that you take a second job, or maybe work OT, and reason that the money is around the same as you would make as a nurse. So, you tell yourself that there's no reason to do three more years of school when you're already making the same money (with OT or per diem work), and then increase your standard of living to reflect that inflated salary. Now, you need the OT to pay your bills and debts. Congratulations, you've now pigeonholed yourself into an EMS career. Again, with that degree, you can up and leave at any time and go back to nursing FT and be happy, knowing how things are in the EMS world.
Edit: If you're still living with your parents, I'd go with the degree first. Your 30 something self will thank you. If you're already supporting a household, you may need to do a medic mill first as a matter of necessity.