Did Gru say "never get older" because of Agnes' innocence?
Native speaker’s answer
Rebecca
"Never get older," or alternatively, "never grow up," is an expression commonly said to children. Gru is indicating his reluctance to let her grow older and thus potentially lose the innocence that children are known for. Ex: My children are adorable. I hope they never grow up. Ex: Never get older. Being an adult isn't all that fun.