Did I grow an apple tree?

This unusual seedling popped up out of a tray where not much else germinated (old seeds). Is it an apple tree? The seed was brown and oval.

If so, what should I do with it? I know most good apple trees are grafted, but Sepp Holzer grows them from seeds. I don't have access to much land (unless I just plant it in a hedgerow). Should I keep it in a container and bonsai it?

I should add, the seed starting mix had homemade vermicompost, which frequently sprouts squash or tomato or pepper seeds.

Why not put it in a hedgerow?  They grow that way all the time here because people throw apple cores ot the window.  When they widened my drive, I had them move one to an empty perk hole because it had such good winter apples.

It looks very like an apple to me. If it grew from a seed from an apple you ate, there is a fair chance that the apples it will bear will be fine, even if the tree is not of "commercial quality".
I personally wouldn't bonsai apples. They'd probably be lovely in flower if you like bonsai, but quite a lot of faff all round. I'd pot it up until I could set it free somewhere. Hedgerows would not be ideal if they are cut back frequently. It would probably be OK in a pot for a year or two and you could look out for a good home for it in the meantime.
Lucky you to get a 'weed' like that!

Thanks, Hans and Nancy. Your comments made me realize that there are a lot of apple trees along the path that runs next to the Erie Canal here where lots of people walk and bike. I never realized it could be from people throwing their apple cores there. So that would be a good home for it.  But I'll pot it up and try to nurture it along in the meantime.

While the cotyledon leaves and the true leaves do look like they could be of an apple tree seedling, the stem looks more like an annual plant: squash and the like.

Still, if you decide to pot it up, and nurture it, please come back and tell us what came of this little plant. I, for one, would love to hear about it. Am sure others would, too☺️.

An apple tree grown from seed will rarely produce the desired fruit and usually needs other apple trees and bees to produce fruit.

The entire process takes many years to find out, but apple trees are awesome and always nice to have around!