You will need to. Otherwise, when you go to update one of your maps, an error will come up saying that you're not the beatmap creator.zhangze611 wrote:
If I change my username, I still have to do My Map, Can I change "BEATMAP CREATOR"?
Spoken English *SO POOR*, sorry
To fix this, you'll need to edit the creator field of each difficulty (either in the editor or by manually editing the .osu files in notepad). Then, while you're submitting, make sure that the "download location" matches your currently uploaded one. Whatever message you had in the text box should be there as well.
Example Submission and Beatmap Info
I'm not sure if this can be done easier, since I was a bit afraid that I'd mess something up when updating (and I don't have any other pending maps to test atm).