When did your kids start "fighting"?
I have 23mo girl and a 9mo boy. Since the youngest has started crawling and is more aware he is alwaaays in her business. He wants everything she has, even when I give him every distraction I can find. When she's in my lap for a snuggle, he's coming right on over the touch her and try to get in too. When they're in their side by side stroller, he's constantly reaching over and she cannot stand it. Screaming and tears for all of these moments.
Obviously he's a baby, but my toddler is having a hard time understanding that. I try to both explain that and teach her to share and also try to side with her like "brother, your sister is playing with that right now, please wait your turn" so she hears me teach him too.
Anyways, did this happen with your 15 mo age gap? Did it get better? Am I doing something wrong to not promote sibling play time? I would just hate for them to never get along when they're so close in age.