Ok, OP, out of 24 years experience of motherhood:
Children do not need a parent who organises every moment of their life to be ideal.
In fact, this isn't helpful. A parent who gets anxious about every minor aspect of life will be sending signals to their child that life is a scary place and that they cannot cope unless things are absolutely right.
But as most of us know, life isn't always ideal. The best thing you can do for your child is model how you cope with that. And that means sometimes letting things ride, sometimes explaining to your child why things happen, sometimes saying nothing at all so that they can forget quickly, sometimes having a quiet word behind their back.
But basically what the child needs is the knowledge that mum is strong and calm, I can tell her even the really scary things because she won't get emotional, I don't have to worry that she will overreact and embarrass me, and I don't have to think about protecting her.
Children with very emotional and reactive parents learn very quickly not to tell things at home. And particularly not the seriously worrying things. Such children are not very safe. You won't want your 12yo or 16yo to be that child, do you? So start working on your unflappability now.
Also, she's only 3 atm and getting emotional is part of her age. But as she grows up, her teachers and peers will (quite reasonably) have different expectations on her: a 10yo who takes everything terribly seriously may well struggle to keep friends. Model what will make her life easier. Start modelling now.