Anyone else’s toddler insane???

Ma

My December 2016 baby has been off the chain! She has been so defiant and awful lately. I feel like we have tried everything: time outs, consequences, redirecting, practicing, and a million other things and she is just so bad! I know shes learning right from wrong but some things she does everyday she knows she is not supposed to do- I know because she’ll say “I go time out” or “I sorry” right after she does it. Today she kicked a hard toy into her 3 month old brothers face. When I put her in time out she hit him. It was the most awful feeling in the world. I felt like I let down my baby because I didnt protect him fast enough (even though I was right there play with them- he was having tummy time and she was playing with his little toy ball that rolls around) and when I talk to my other friends with two kids they’re always like “oh no my oldest loves the youngest- he/she never hit the baby” and I feel like I’m failing because I can get her under control. And I don’t think it’s because she feels like her brother is getting all of the attention because she is- positive and negative attention. He takes long naps and we have plenty of snuggle and play time. I just feel like a crap mom... please tell me I’m not the only one 😔