Cyndi,

44 was not too old to serve in the Confederate army. The Confederate army included boys of 14 and elderly men in their 60s and even 70s--when you're defending your homes, anyone who can carry a musket will get invited to serve. Toward the latter part of the war, the Confederacy was conscripting (drafting) men up to the age of 50.

There was a "Carroll A. Lindsey" who served as a Private in Company D, 24th Mississippi Volunteer Infantry Regiment. There was also a "C. Lindsey" serving as a Corporal in Maj. John B. Dunn's Mississippi Rangers battalion--the latter were six-month state militia rather than Confederate volunteers. The service records for both can be accessed at the National Archives in Washington, D.C.

It is also possible that he may have served in a different unit--Confederate records are incomplete, and when Grant had his troops burn Jackson, MS, a lot of the records on the State militia were likely lost as well.

Hope this helps.