Please don't let any of the other posters scare you away from a wonderful field. They are right in many regards- however, like you said, you are willing to work hard so you can definitely do this. I'm not good at math or chemistry, 2 required pre-requisites for a bachelors in nursing, but I studied (while working full time and raising a child) and I passed. Then I went on to graduate in the top 5 of my nursing class with honors. Nursing isn't about math. It's about learning how to think critically. It's about understanding how the body works, anticipating doctors' treatment plans, assessing, documenting, educating.
As for the "finding a job" portion, yes it is certainly more difficult than it used to be. That being said, I graduated a year and a half ago and I had 3 job offers upon graduation whereas a third of my class did not have any offers. Being a CNA or tech somewhere helps because it gets your foot in the door at that facility and it also looks good on a resume if you apply somewhere else. That's how I got one offer. For the other 2, a couple months before graduating I started calling hospitals and speaking with their nurse recruiters about jobs I had seen posted on their websites. After speaking with them, I filled out applications for jobs that they said didn't require experience. I got interviews! And then offers. Maybe my name was still fresh on their memory from our conversations, I don't know, but it worked.
Anyway, my point to all of this is that there ARE nursing jobs out there, even for new nurses. In fact, I was browsing the internet for nursing jobs in my area and found 10+ listings for psych positions, half of which did not ask for any experience. The thing is, you have to make yourself marketable. Get good grades, be a CNA or a tech in a hospital, make phone calls, create a good resume. If you have time, volunteer at a hospital too. It looks great on a resume. Plus, if you volunteer somewhere that has a psych unit then you can do some networking.
Good luck to you! Nursing is a tough job, but rewarding. If you want to do it, don't let anyone stop you.