In desperate need of parenting help !!

I am dumping my brain here .. I have always felt that my daughter is way too strong headed than kids of her age…but lately it’s sort of extreme. Especially since I went back to work after my second maternity leave. She is a micro premie. Born at 24 weeks of gestation, 1.3 lb, 620 gms. Now birth age 3 yr 2 months, corrected age 2 yr 10 months.

When my 6 month old son wasn’t able to sit and roll and fall she used to find it very funny and laugh her head off. Now he can sit. So She is pushing him for the past two days so that he rolls and falls. I am constantly teaching her nicely that she shouldn’t do it. Baby gets hurt etc. but while playing she is doing it again and again.

Today she did it several times and I had a personal time with her , sat with her , explained.

She absolutely doesn’t have any I’ll intent .. to actually hurt baby or fighting with him. She is just playing but a bit harsh.. when I speak with her , she listens quietly.. and realises that she did something wrong. Doesn’t make eye contact .. keeps her head down etc etc..

I have told her 5 to 7 times today.

Then at night my son was sitting in the bed, I am expressing and she pushed him hard with both hands . He fell backwards and head hit the mattress.. it was a loud bam and my mum heard it from the next room.

That’s when I got very angry. I just yelled at her saying just her name and kept staring disapproving what she did. And that’s when all of it started. She kept staring back at me with a determination on her face. My husband came and he also kept looking at her . At this point she is perfectly aware that she did wrong and we both are unhappy. But she held her ground. Absolutely strongly. My husband asked her to say sorry to baby .. and she remained determined that she won’t say sorry. We decided not to let go easily today. So we kept waiting .. talked her into it. She was absolutely quiet and kept looking back at us and kept her mouth shut. She tried to come up to us and get on our laps but we both said that no. You first say sorry to baby. But she didn’t ..

Absofreakinglutely didn’t.

My mum came and picked her up to diffuse the situation.. I was like it’s ok if she says sorry even to my mums ears. But she couldn’t get through her either. She was in this full war mode with both of us. Cold and steel. I am terrified .

I know siblings will have their push and play and hurt and hug times. So her pushing is not the main problem any more. It’s the fact that she is not corrected age 3 yet and held her ground so destructively is what scared me so so so much.

I don’t know what to do or how to discipline her ..

I kind of sent her to a corner on the bed .. sort of a time out. She went and sat with a face like steel. We wanted to give her a out again and again. But she didn’t take it. I don’t know what to do or how to discipline her .. None of us shout. We won’t ever by able to give physical punishment. We believe in gentle parenting. Plus my heart hurts always for her for the fact that she has spent 4 months nursing under machines like a lump of life. Please help.