I don't think so its something to worry about. My elder son used to do similar things when he was around 4 years old and he stopped it on his own by the time he was 6 and half years old.

I have a cousin who used to write reverse, may be because she is left handed. But after 6 or 7 years of age she was writing like us. So, I think that its just a phase when many kids do like this. May be they are not able to understand whats reverse.

Just chill you daughter will write properly when time comes.

I don't think there is anything to worry. This problem is quite common in kids of this age. I suggest that you keep trying by making your daughter practice more. But don't force your daughter, try to make the practice sessions into an interesting game and probably join her in this game.

Its normal for kid of this age to write mirror image/backward as by this age children are still not good at "directionality". Its till the age of 6 that they get perfect with it.
You can help your child learn directionality by playing games with him. Like you can put his ball on a table then under it etc. , both of you take turns doing this.

Similarly you can ask him to raise his right hand then left hand etc. You do the same thing.

Hope this helps.

What a great skill.
Even we elders cannot do this.

I have come across 2 to 3 pre school kids doing so. So, I think it is something which most of the kids of that age go through.

Oh my goodness! an amazing article dude.