The chorus is totally Gaga... A definite hint of "Edge of Glory" in it I think... I have to say, I don't think it packs quite the same punch that the chorus of that song does... It's like you're going for it, you're going for it, you're going for it, but then you back off a bit, where Gaga would keep going and sock you right between the eyes... BUT it is really good and catchy.
I thought the verse was maybe a bit too clean and bit too guitarry.. The lyrics work; they're not the star of the show for me (that's the chorus, which totally has star quality, as it should!), but they're good, fun pop fare.
I also generally dislike key changes and I totally echo shadowfax's sentiment on them..... But more to the point, I don't think you need it, particularly if you decide to trim some of the length.
Also, someone mentioned they thought the bridge/pre-chorus was too long...I was thinking the same on that too. You've got the four lines of the verse which essentially just repeat, which I think is fine for the verse, but when the pre-chorus does a similar thing, I think it's crying out for a quicker lift and change into the chorus.
But overall, I totally agree with most other commenters that you achieved your goal of young, fun, female power pop really well, and with a bit of tweaking, I'm sure there's an artist out there who would love to take this on.