At the moment, Firebase doesn't stores the data in the order it is entered. For ex - There could be 2 existing childs and a new child is inserted, that new child goes and sits in the middle of the already existing ones! I guess this works by alphabet order but I want to store data in the correct order only.
//Could insert anywhere
It is not possible to insert data into Firebase into a desired position. Firebase data is sorted alphabetically and all newly inserted data will be rearranged accordingly.
Use query rules to return the data in the order you want.
You are correct about
push(), it will always create a unique key and add to the end, just as pushing to an array will add to the end.