3 year old behavior and siblings

I need help. My sweet little boy is really misbehaving and I don't know how to help him. He wants to wrestle with DD who is 1. He is 3. Obviously this makes DD cry. She is not as big or strong as he is. How do I get him to understand that he is bigger than she is and she can't wrestle him like he wants to do to her?
DH and I try to model good behavior. I am really at a loss. Time outs are not working.

Also in the past 6 months DS has stopped eating almost everything except a few things like chicken nuggets. Where did my good eater, good listener go? If anyone has any advice please I could use it.

Re: 3 year old behavior and siblings

This is all age appropriate behavior.. my kids are similarily the same age difference..

Re: 3 year old behavior and siblings

We are going through something similar. DS #1 is 3 1/2. DS #2 is 15 mo. To be honest, they like to wrestle with each other but sometimes my older DS can be a little too aggressive. I try to tell him he has to be gentle because the baby is smaller than him and he can hurt him. He usually loosens his grip

It's all age appropriate behavior as the PP said.