Amazing story I think most apple trees are grafted onto faster root stocks for faster growth and to limit size so apples can be easy to picked but in no expert the only other thing I can think of is if the tree cannot pollinated for some reason either by insects or the tree is either male or female and might need a partner to be grown to aid successful pollination

welcome to GoY and well done to your daughter on growing a lovely tree.
many apple trees need to have another one nearby so it can pollinate. if the tree gets flowers then it is possible for it to get fruits. The flowers have both male and female parts but many varieties are self sterile.
Do you know which variety of apple she got the seed from? if you do then you may be able to find out which pollinator it needs.

Sadly though Apples are considered to be the most variable from seed of all trees. Yes, your tree may well produce fruit, however the chances are that the fruit will be small and what is colloquially referred to as "spitters". One bite and you spit it out. The famous apple seed planter in America, Johnny Appleseed was more interested in Cider apples than culinary ones so the sweetness etc was not that important.
Having said all that, there is always the chance that you could have a new delicious variety. My mother in law grew one from seed and that had lovely big apples on it.
Another consideration is the eventual height of the tree. They can grow up to 30 feet or more in height.
Good luck with it.

Agree with previous answer - and its also not unknown for apple trees grown from pips to have thorns... you never know what you're going to get in terms of height and spread, never mind what the fruit will be like. But it'll be interesting to find out... if there's a crabapple tree in the vicinity, that could pollinate it...

Love apple trees , I really hope you get some fruit.

If there is no pollinator fairly near you might try my trick - I took a small spray of flowers from one that was in flower at the same time - I think it was from a random tree that had grown from a discarded core by a nearby footpath. I stood it in a jar of water at the foot of the tree and hey presto the bees visited both and I got apples!

Well there we go , or you can expose the inner of the flower by removing the petals and rub that in the flowers on your tree , but that's only really viable for a tree you have kept small .