Presumably a graduate from Texas A&M (the other organization identified).

Yes. Texas A&M Aggies.

Utah State's mascot (The college) is also the Aggies. Seems like it is probably more likely that.

You're replying to the person who used the term "Ags" upthread.

That mistake is actually kinda funny given the post this comment thread is in. I suspect that's why they would assume the reference was to USU's mascot. It makes sense if one happens to miss the details of who commented what.