Background: I am a Spanish interpreter in my late 20s who started learning the language at age 12. Before I started learning Spanish, I had three (non-consistent) years of French. I think my accent in Spanish is decent as it is, especially considering that I am a non-native speaker and I started studying at the close of the window of opportunity. People have given me some positive comments on my accent, but the comments have mainly come from monolingual English speakers. (One native speaker from Puerto Rico said that I speak Spanish better than he does!)
Is it too late to improve my accent? I think it could improve.