I found a 03 Avalanche HIGH MILES???

I bought a 2000 Silverado Ex cab Z71 . It is sharp truck it has 107,000 I bought if for $9,000. I'm have a ad in paper and have offer for 12,000. Which I'm going to take.. I have wanted a Avalanche for a long time. I took out a $9.000 loan. for my 2000. . I could now buy UP and get something nice and finally get my Avalanche a 03. Cars.com . But... this truck which has everything, heated seats sun roof, Leather everything. One owner the Car Fax is clean as a bell.. another BUT... It has 158,000 miles.. The truck is in Texas. He said he he would sell it delivered to me $12.. Ok guys lay it on me with your thinking.. 158,000 miles might be just to high. It would be a work truck.. I have a 92 Z71 farm truck. 254,000 miles on it