Let me start by saying that you shouldn't feel bad for spending 6 years on a 2 year degree. I did the same. When I started college, I didn't put my heart and soul into it, so I didn't get very good grades (mostly B's, with a few A's and a C or two). My GPA was too low to get into the nursing program
, so I had to retake some classes in order to bring up my GPA. It didn't work. I ended up transferring to a private university (5 times more expensive, but the admission standards weren't as high). I took a year off when I got pregnant with my daughter. When I finally put my mind to it, I did very well in my actual nursing classes and graduated on the Dean's List. It took longer than anticipated, but I made it.
If you're not sure about RN now, you can start with LPN. Quite honestly, there isn't THAT much of a pay difference. At least, not in my area. LPNs start around $15/hr and RNs start around $18/hr. LPNs are more limited, though. The hospital I work at will not fire LPNs that have been employed for years, but they will no longer hire them. RNs that have an ADN are limited as well, since there is a push for BSN educated nurses.
If you start with LPN, you can always go back for RN. The school I graduated from offers a LPN-RN program. It's a year and a half program, if you go full-time.
Bottom line is, do what makes you happy. If you want to do your schooling in steps, there's nothing wrong with that. You'll still be a nurse.