There is excellent scientific evidence that the Earth is young. (See: Dr. Hovind's Seminar #1)
Also, there is a good book on-line, free to download, It's a Young World After All by Dr. Ackerman: http://www.creationism.org/books/ackerman/
Modern Biblical scholars disagree on the age of the Earth. However, until only a few generations ago - Biblical scholars did NOT disagree!
For thousands of years early rabbis and later Christian teachers (for almost 2000 years) read Genesis 1 as a literal account. The Earth was seen as created from nothing about 6000 years prior to today. Not 7,000, not 6,500 - but 6,000 years old. Bishop Usher's date was calculated at 4004 B.C.
Only in the past 200 years, as evolution has taken hold in men's minds, has the belief in "longer ages" become prevalent. One pivotal verse in the modern creation movement is not in Genesis at all. And it has motivated many a modern creationist to affirm that the Genesis account of Creation Week should be taken literally. Here is how the logic goes and the Scripture reference:
There were about 40 human authors for the 66 books of the Bible. All is inspired, correct? There is even one portion written by God's own hand! ...It would seem that "if any part is really, really inspired" it should be the part that God penned Himself, correct? Well, please read these words from the middle of the Ten Commandments:
Exodus 20:11 "For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it."
The first issue that Dr. Hovind deals with in his extensive Seminar Series (see link above) is the age of the Earth. Once resolved, that there is excellent evidence to show the Earth to be young, he continues with other topics like the "cave men" the "radiometric dating methods" et cetera.
We do not know how long Adam & Eve were in Eden. We do not know
the time frame of that portion of their lives, but we are told exactly
how many years Adam lived (930 total), and we know that they had children
(Genesis 5:4-5) besides Cain, Abel, and Seth; with Seth being born when
they were at 130 years of age.