"...6000-8000 yrs. Or is this JWs view only for the age of the earth?"
It is a misunderstanding that JWs view the earth as 7000 years old, or thereabouts. Here are a few quotes from the literature showing the earth can be billions of years old according to Watchtower beliefs.
(Young People ASK 2 chap. 36 p. 301 How Can I Defend My Belief in God?)
The Bible says that the earth and the rest of the universe were in existence before the first creative day. Thus, the earth and the solar system may well be billions of years old.—Genesis 1:1.
(Awake 3-22-83 p13, Article: Evolution, Creation, or Creationism—Which Do You Believe?)
If geologists want to say that the earth is 4 billion years old, or astronomers want to make the universe 20 billion years old, the Bible student has no quarrel with them.
(Awake 11-22-81 p13)
Nevertheless, with proper attention to such possible pitfalls, acceptably reliable dates have been put on many old rock formations. Based on this method, the age of the oldest parts of the earth’s crust has been set at over four billion years.
7000 years used to be viewed by JWs as the length of each creative period (day), but that has been abandoned. Now the Society says this...
(Was Life Created, Brochure (2010) p24)
"How long, then, were the creative days? The Bible does not say; however, the wording of Genesis chapters 1 and 2 indicates that considerable lengths of time were involved."
So, the Creative Days are no longer viewed as being 7000 years long, but as an unspecified “considerable length of time.”
Furthur, JWs view Day 1 of creation a little differently from other groups. Day 1 started, not with the actual creation of the earth and other heavenly bodies, but with the creataion of light. In other words JWs believe the earth was already here when the 7 Creative Days began, and those Creative Periods involved preparing the earth for plant, animal, and human life.
Here is a chart from the Insight Book, p27, showing the Society's view of the Creative Days.