True Christians should base all of their beliefs on the Bible. So when Jesus Christ pointed to the Genesis account as true history, we need to take that as fact.
Jesus spoke of Adam and Eve as real people. At Mark 10:5, 6, "Jesus said to them:...“From [the] beginning of creation ‘He made them male and female." He referred to their marriage when explaining Jehovah’s standard of monogamy. (Matthew 19:3-6)
Also, Luke’s Gospel account traces Jesus’ genealogy all the way back to Adam. (Luke 3:23-38)
If they never existed and the garden in which they lived was a mere myth, then either Jesus was deceived or he was a liar. Neither conclusion is feasible! Jesus had been in heaven, watching as the tragedy unfolded in the garden. What evidence could be more convincing than that?
In reality, disbelief in the Genesis account undermines faith in Jesus.
Was the garden of Eden a real place? (w11 1/1 pp. 4-9; Watchtower Online Library)
Why can we believe that the garden of Eden was a real place? (w11 4/15 p. 28; Watchtower Online Library)
Why Eden Matters to You (w11 1/1 pp. 9-11; Watchtower Online Library)
Where Was the Garden of Eden Located?
(The following is an excerpt of the WBTS publication, Insight on the Scriptures, Vol. 1; Eden; Location of Eden):
The original site of the garden of Eden is conjectural. The principal means of identifying its geographic location is the Bible’s description of the river “issuing out of Eden,” which thereafter divided into four “heads,” producing the rivers named as the Euphrates, Hiddekel, Pishon, and Gihon. (Ge 2:10-14) The Euphrates (Heb., Perath′) is well known, and “Hiddekel” is the name used for the Tigris in ancient inscriptions. (Compare also Da 10:4.) The other two rivers, the Pishon and the Gihon, however, are unidentified.—See CUSH No. 2; HAVILAH No. 1.
Some, such as Calvin and Delitzsch, have argued in favor of Eden’s situation somewhere near the head of the Persian Gulf in Lower Mesopotamia, approximately at the place where the Tigris and the Euphrates draw near together. They associated the Pishon and Gihon with canals between these streams. However, this would make these rivers tributaries, rather than branches dividing off from an original source. The Hebrew text points, rather, to a location in the mountainous region N of the Mesopotamian plains, the area where the Euphrates and Tigris rivers have their present sources. Thus The Anchor Bible (1964), in its notes on Genesis 2:10, states: “In Heb[rew] the mouth of the river is called ‘end’ (Josh xv 5, xviii 19); hence the plural of roʼs ‘head’ must refer here to the upper course. . . . This latter usage is well attested for the Akk[adian] cognate resu.” The fact that the Euphrates and Tigris rivers do not now proceed from a single source, as well as the impossibility of definitely determining the identification of the Pishon and Gihon rivers, is possibly explained by the effects of the Noachian Flood, which undoubtedly altered considerably the topographical features of the earth, filling in the courses of some rivers and creating others.
The traditional location for the garden of Eden has long been suggested to have been a mountainous area some 225 km (140 mi) SW of Mount Ararat and a few kilometers S of Lake Van, in the eastern part of modern Turkey. That Eden may have been surrounded by some natural barrier, such as mountains, could be suggested by the fact that cherubs are stated to have been stationed only at the E of the garden, from which point Adam and Eve made their exit.—Ge 3:24.
After Adam’s banishment from the paradisaic garden, with no one to “cultivate it and to take care of it,” it may be assumed that it merely grew up in natural profusion with only the animals to inhabit its confines until it was obliterated by the surging waters of the Flood, its location lost to man except for the divine record of its existence.—Ge 2:15.
In any event, the Garden of Eden most likely was located in the Middle Eastern region.