Does the phrase "just gonna/going to go" a common expression?

Native speaker’s answer
Rebecca
Yes, it is a common expression! It has a couple of nuances, such as doing something without thinking too much about it or getting too nervous, a single action or thing to focus on, like it is here, or that you're going to do something quickly. Ex: I'm just gonna go to the shops quickly. Ex: She's just going to do her best to sing the song even if she messes up. => focus on having fun Ex: I'm just gonna go to my appointment, go home, and avoid talking to anyone.