"It's hard to describe the love you feel for the first time when you hold your child," the 25-year-old country singer wrote on Instagram. "I will never be the same. Asher James, I promise to be the father you deserve. And Hannah, I promise to be the husband you want and need. I love you both so much. You've given me everything I never knew I needed. Welcome to the world Asher James Mooney."