My youngest was 8 months old when I opened, but when she was born my daughter was 4 and my son had just turned 3. I was worried about my son accidentally hurting her or throwing something on her, too. Instead of a large swing, which I thought would be unsafe, since he could get behind it and push it way too hard, we got a little travel one. It fit on top of the kitchen table, or on a wide counter, and that way I could put her in it and he couldn't push it. Those little bouncy seats usually fit on tables too, I think. They have rubber feet so it doesn't move. Obviously I never left the room when she was in it, but it helped to have somewhere to put her where he couldn't reach while I was making lunch or something.