Kindergartner Troubles At School

Dear OP,
I am not very good at sugar coated replies. So please do not assume that I am being rude. I am not.
Sorry if my reply offends you.

Did you ever teach her that all kids are smart in their own way and that What one kids is smart at does not necessarily become a scale at which every other child is measure for smartness ?

Your child might be doing well in academics but the other kids might be doing exceptionally well in creative subjects like art/music etc. Thats an achievement too. - did you discuss with her about this possibility at all ?

I am a mum of 2 kids, so I know what you feel about your child and how proud you are of her.
It is absolutely understandable. Just the way how as a parent it is our responsibility encourage the child to do her best and to win and to give her 100% it is also on us to prepare them to accept the failure and to take failure gracefully and to acknowledge that there are other smarter kids out there and the beauty in being smart comes from being humble.
If we don't teach this at home , society will teach this - and when society teaches it is not a great experience for the child.
Though it's important to tell her that she is smart and pretty, it should not make her think that there is no one else who can be smarter and prettier than her - such things develop unnecessary attitudes(which make it hard fo rthem to develop good friendships later on) in kids which we do not realise now and by the time we realise it would be too late.

Instead, tell her that just as she is smart in academics, all kids are smart in their own sweet way. All kids are pretty in their own way. There is no scale to measure the young tender minds - there should not be any !
Fully agree with @Rihana here - most kids to really well in kinder and grade 1,2,3. The reality comes in, in grade 4 onwards.

To help kids academically there are private tuitions. But to help a child grow to be respectful towards her peers and her teachers and other elders and to just respect other regardless the level of smartness - there are no such tuitions or classes. This has to start at home from day 1.
I am not saying don't praise your child. All I am saying is please tell her she is like any other child - and that all kids are excellent at something or the other.