S.H.
Unless your Pediatric Dentist has concerns, I wouldn't worry about it right now.
Your child is still young.
My late Dad had an underbite, and I did too... which was corrected via braces when I was in 7th grade. BUT, in those days, the Orthodontist wasn't the best... and they pulled out more teeth than necessary, prior to me getting my braces. The Orthodontist said my mouth was crowded, and I had too many teeth, whatever that meant. Regardless, my present Dentist says that now, my lower teeth was pushed back too much... and so my lower front teeth hits my top front teeth... and my bite is not ideal.
My under-bite was not pronounced, just slight. It was not an 'aesthetic' problem, and I never suffered as far as appearance or 'beauty' terms. If that is what you are concerned about. It never bothered me personally.
The thing is, your child is quite young... her permanent teeth is not even in yet. And their mouth structure is still forming & changing... so if anything just ask your child's Dentist. Then gauge it then, and see.
In my case, it seems to be hereditary... my son MAYBE has an under-bite, depending on how we look at him. But it's not pronounced. We don't worry about it. It may or may not go away. AND, it depends on how their formation of their mouth is, later, as a teen/adult. For him, I would be against braces, if it poses no problem.
My late Dad, with his under-bite, looked quite handsome and distinguished if I may say so myself. And he never had any dental problems beyond the "appearance" it. Of course in his generation, they never used braces.
Until the teens, and when permanent teeth comes in... I REALLY doubt, a Dentist would put braces on a child so young as yours. Their mouth WILL change and their 'bite' will change too. Even after my braces came off, my mouth retained it's 'memory' of my natural bite.. and to this day (as an adult and since my braces were taken off in 10th grade), I have to wear retainers... to keep my lower teeth from shifting back to it's original formation. And if I do not wear my retainers, I can feel my teeth STILL shifting back. It's NOT a permanent solution. KEEP this in mind.
I personally wish, I had not had braces...
All the best,
Susan