Well, I'm certainly not an expert, but if a friend made a suggestion then you might as well start there.
Ten years is a fairly long time. It's not like the National organization has a sign up with your picture on it saying DON'T INVITE THIS WOMAN!!!
You don't have to rule out an organization just because you weren't invited during informal recruitment. I, personally, would feel a little uncomfortable, but that's just me. I tend to be shy.
I think it is a good idea to look beyond your campus. Unless you went to Penn State or another school with a huge Greek system, you only saw a small proportion of the NPCs. That being said, you need to find a sincere connection with an organization, a connection on which you can build a love for the group. For example, my first big connection was with the philanthropy.
Again, I strongly encourage you to follow your friend's lead. At least initially.
LM