Adopting a pen name isn't just a matter of rearranging your name. A successful pen name will be with an author for life. In fact, in might even take her over eventually. For that reason I'm glad I kept my first name. I know many authors who've changed the whole thing and then friends are never quite sure what to call them. The author doesn't care--call me whichever, they usually say. But people like to know they are addressing you correctly and when you have multiple names, that can be a challenge.
On the flip side, a new identity can bring all kinds of new and exciting thing. Personally, I'm hoping Erin Quinn is a little taller than Erin Grady was. I'm hoping she is thinner too. And of course it goes without saying that I hope she's a helluva lot richer! LOL.