http://www.sos.mo.gov/TIF2PDFConsumer/DispPDF.aspx?fTiff=/archives/AdjutantGeneral/Civil_War/ServiceCards/s866/1769.tif|/archives/AdjutantGeneral/Civil_War/ServiceCards/s866/1770.tif&Fln=S167360.pdf
His card lists him as 18 at the time of enlistment and there is a blurb on the back of the card from the Missouri Historical Review. His service appears to be primarily the Winter of 1864 through May of 1865.
John R