Nice book along with your chosen heading too.  I got some books of her signed as well from the Powergirl title, it's odd though cause they were signed on the same day but her signature is somewhat different than yours cause they had labeled it as signing & sketches...

She used a thinner marker to sign it seems. Looks cleaner than thicker sharpie sigs. This is the first sig book that I have that looks like it was signed with a thin tip marker. Looks to me like the same color as the lips too. I could see that being the last part of the sketch, and she just used the last marker to add the signature rather than swapping for something else. I think you can see how the earlier art influenced the Power Girl design.