HELP! 🤧 14 month old takes off her diaper

I'm a ftm, my daughter is almost 14 months. The past 5 days she has been taking off her diaper whenever it's full specifically immediately after a poop. Today she took off her diaper and I did not realise until she sat on me 😫 I search for the diaper that I still haven't found but I found her poop 😭😭

WHAT DO I DO? Do I buy pull ups? Do I start potty training a child that doesn't speak with words yet?