Stubborn and determined

I went back to work. I love work. I love uninterrupted conversations with adults 2 days a week. It's a work in progress for Ava to drink from a bottle still (poor Robby) and still, after more than 2 years, we daily work on Riley's sleep. It's all temporary. I keep telling myself this. It's all temporary. At the same time I don't want them to grow. Where does their determination come from?