Your right, both of the Texas ones are out as they are in their 40's.

Looking at the image I would say it looks like an early war picture and as he was 22 in 1861 he probably enlisted then or as soon as conscription was enacted.

There is a B. F. Lowe in the 21st Tenn Cav but he didn't enlist until 1863 and there is no age given.

There is also a Benjamin F Lowe who served as a 3d Lt in the 3rd Ark Inf, no age given but his record includes a request for information (normally for a pension) from Texas .

Need to run that one by Bryan Howerton on the Arkansas Board and see if he can add any info.

Alan Thrower
England