3000 years old is a conservative theory.
http://articles.baltimoresun.com/1996-02-05/news/1996036054_1_samaritans-mount-gerizim-torah
Here is proof that the Hebrews of 3000 years ago were literate ;
http://blog.dovidgottlieb.com/2011/05/3000-year-old-hebrew-inscription.html
Whilst not providing PROOF that the Torah was written at least 3000 years ago, the inscription fairly powerfully demonstrates the existence of the Jewish religion ~1000 BC :
http://www.livescience.com/8008-bible-possibly-written-centuries-earlier-text-suggests.html ; the poem is directly reminiscent of the Biblical texts, and demonstrates that a textual religious tradition of Hebrew language and religion certainly existed at that time.
Here is a presentation of some basic facts about the History of Religion (which BTW dates Judaism to being about 4000 years old) :
http://www.wisegeek.org/which-are-the-oldest-religions-in-the-world.htm
There is a certain amount of confusion as to the dating of the Torah, because the texts as we have them now, for the Pentateuch in particular, seem to have been edited into their present form in about the 6th century BC -- the notion that they were therefore
written in that period is derived from some contents that were added at that time.
One has to remember though, that these were also
legal texts, so that prior to their having gained a status of being sacred, it could have been considered normal to continue revising them as according to the evolution of the Law.
Of the older books in the Histories though, the oldest is typically dated to about the 8th century BC -- and the original texts of the Torah itself can only have been earlier than this, a complementary volume not being possible except on the basis of an original textual corpus.
The latest texts included in the Christian Old Testament were not written until 1st century BC OTOH, the Septuagint translation often used by Christians having been produced in the 2nd Century BC, whilst the Jewish canon of texts was established in late Antiquity, collecting texts whose final edited forms were produced between 8th and 3rd/2nd centuries.
There is however no real argument against the proposition that the Pentateuch in particular underwent a process of evolution prior to reaching its final form in about 6th century BC, and it is a conservative estimate, based on archaeological, linguistic, and internal evidence that this process will have taken at least 200 years before the oldest extant text in the Bible was written.
The Myth of Eden is
probably older than 3000 years old, and probably bronze age, whereas the Torah likely began to be written per se at least 3000 years ago. I am unaware of any serious objections to this theory ; the only serious objection that did once exist was that Hebrew script had not been demonstrated in that period. Not only did it exist, but the extant sample that we have of it contains what seems to be a direct reference to the contents of the Hebrew Law, if not to the current texts of the Torah. The discovery is supportive of the existence of the Torah in about 1000 BC, and supportive of the Jewish Tradition that this is the age of the work -- notwithstanding its editing over a 400-500 year period of whichever original contents.