I agree with Michele....yet, at the same time....LOL.

I've discovered that some simply do not share (what may be innocent and harmless fun and humor) as genuine humor.
Apparently, she is sensitive to such humor, especially when it directly (indirectly) relates to her personally.

Personally, (and with my sense of humor), I'd receive that for what it was....funny. However, that does not mean that it really is funny to her.
As Michele already mentioned, make another attempt at explaining it to her with a bit of empathy applied....ensuring her that your intentions were just that of random humor....and NOTHING meaningful outside of that.....mere play.
(Her age only tells me that she must surely be sensitive to such behavior....all the more reason to tread lightly with any future related play).

All the best & good luck.

Shangrala