LOS ANGELES -Carrie Underwood doesn’t know if she’ll ever ‘’figure out’’ raising two children. The 36-year-old singer and her husband Mike Fisher welcomed son Jacob - a sibling for four-year-old Isaiah - into the world in January and she admitted they are still adjusting to life as a family of four. She said: ‘’We’re still figuring out our groove, to be honest. ‘’I don’t know if we’ll ever figure it out.’’ The ‘Love Wins’ singer is delighted Isaiah has taken to life as a big brother really well, admitting there is already a ‘’really cute’’ bond between her sons. She said: ‘’He loves it. He calls Jacob ‘My baby.’ [He says] ‘Where’s my baby? How’s my baby? I wanna kiss my baby.’ ‘’ Last month, Carrie admitted she’d found it hard for her body to ‘’bounce back’’ after giving birth to Jacob and she thinks it’s important to show that even famous people struggle with the same challenges others do.