I liked the idea...the size is definitely too big though. o.o
Try making your sigs smaller, preferably 400 x 140 or somewhere around that range.
Also the background....well, I wouldn't really expect lightning behind such a sweet a girl and a cute...dog? lol
The text is too big...try to make the sig have a nice color flow, so that everything looks good together.
But it's nice for your first one.