Do you think it might be because she is ready to potty train? Is she showing any signs of being ready? Maybe check out the potty training board on here for more info. On average girls are ready between 2 and 2 and a half.
Mine is just the same, 22 months, and friends girls too.... Just imagine if someone wanted to change you all the time and just laid you down against your will and wiped you with cold wipes.... I think I would complain too! I like to see it as a development of their own personality (and a soft toy or phone to distract her helps too!)