First of all congratulations!
Go for FNP for the widest opportunites, it removes a lot of limits.
I wondered the same questions before I started school and figured out my guesstimated salaries and loans etc to figure out if the np was financially feasible for me. I had estimated current salaries to be on the low side, but still figured it would take me about 7 years of work to 'break even' everything else after that would be above and beyond what I would've made as a nurse. For me it was worth it.
It definitley fits me career needs and personality (not to mention aching back) a bit better. 1 yr ago I had considered a nhsc eligible job salary 75$ per year + 50K for student loans in return for a 2 year contract. I did not go this way for a couple good reasons and I took another job 15K a year more salary, with no student loan payoff.
I have not regretted anything. I have only made minimum payments on my student loans....but still, I have found my np career to be financially rewarding, personally satisfying and intellectually challenging.
I kind of think that if you are considering this at this age, you should probally go for it? Many more pt ooprtunites exist that I think would be a good fit for me after I retire. I am not sure I could continue the physically strenous part of being an RN for nearly as long.
Keep us posted!