If you really don't want to conceive, but want to use NFP, then I really suggest that you chart for about 6 months. Not having had your cycle back yet it makes it scary to just take the leap and use barrier contraception (you could also use barrier + withdrawl if you are really worried).
While using NFP, I really didn't have any worries. You can clearly see that your fertility is really cyclic (duh, I know) and when you figure all that out, it's a cinch! But, you really must use something else before you figure it all out. Once you figure out how your cycles are, then you could use super strict rules and just avoid penetration during the times that you are potentially (or about to be or just were) fertile. (I'd suggest if you ovulate early, avoid pre-ovulatory sex, as the result of our 5 day pre-O sex is a new little one.) I'd use NFP again in a heartbeat though, with a little more experience under my belt!