You can DO IT!
I just graduated with my ADN in May and took my RN boards on Tuesday (And passed! I'm an RN!) But I had many of the same reservations as you did. I was also not so hot with math and science and I thought nursing would be "too hard" for me. Well, it was a challenge but I found out that it is my PASSION. When you love doing what you do.. it gives you the motivation you need to succeed.
If this is what you want, go for it! There are a lot of great programs out there that allow you to go part-time. I've also been toying with the idea of midwifery but there isn't any place close to my hometown that offers it as a Masters program. I've been leaning towards Nurse Anesthetist recently.. but we'll see. I start working towards my BSN this fall and I plan on doing it bit by bit.. little at a time.
GOOD LUCK!