Hello of course all the trees created were in the Biblical Garden of Eden which is a place of the future but one of the first stories made by God. It is naturally up to humans to decide that the tree of knowledge was an apple tree, although the Bible does not disclose this information. It is not wrong to try and guess which fruit the tree was. In addition, the reason for the Biblical stories is explained as:
Romans 15:4
Easy-to-Read Version
4 Everything that was written in the past was written to teach us. Those things were written so that we could have hope. That hope comes from the patience and encouragement that the Scriptures give us.