I have been a domain investor/owner since the 90's so I can tell you with absolute certainly that those automated appraisal websites are a joke for anyone who knows anything about domains. DO NOT take any of their estimations as meaning anything other than a form of entertainment. Sometimes they can tell you if a domain has some value, sometimes, but exactly how much or even in the ballpark is more rare than winning the lottery!
Those automated appraisal websites base the value of a domain on whatever their programmer or whoever wrote their algorithm thinks a domain should be based on. Do some research and you will find out that anyone that really knows about domains consider automated appraisals as a complete joke.
Also, domain age usually means nothing except with a very certain type of buyer. This used to be something that mattered years ago, a little, but not much lately. Usually domain age only matters to new domain investors (domainers) who think it matters. What the name is, what it's potential uses are, what it's past life (sometimes) were and what happens to be hot at the moment are more important factors to determine a domain value.