Well in between my first 2 I had 2 miscarriages but my oldest only knew bout one and she was 15 months and excited but little clueless. It took while to get pregnant and stick. So when my second came along my oldest was 3.5 and she was ecstatic. When the baby came she had few issues understanding how when she would cry and throw fit she would be sent to room a d baby could cry whenever she wanted lol but otherwise she did good. And has with my other 2 as well