I got a question for you: "As Good as I Once Was" is a song co-written and recorded by American country music singer Toby Keith that reached the top of the Billboard Hot Country Songs chart. This song and his 2003 single "Beer for My Horses" are both his longest-running Number One hits, each having spent six weeks at Number One. "As Good As I Once Was" was released in May 2005 as the second single from Keith's album Honkytonk University. Keith wrote the song with Scotty Emerick.

Based on this passage, who sings i'm not as good as i once was?
Let's think first:
To answer this question, we should know that: "As Good as I Once Was" is a song co-written and recorded by American country music singer Toby Keith that reached the top of the Billboard Hot Country Songs chart.
Therefore, the answer is Toby Keith.