Anyone can/should be able to learn Spanish. I think we're just pointing out that 3 months to be "fluent" is an outlier. A year is more accurate, with intensive study and practice (as in daily). Ad again, I would say at a year, most people if they are conversationally fluent, are in good shape. I don't know anyone here (including friends that are 100% fluent) who can "pass as Argentine", even after several years of living here. They are 100% fluent but still, the accent is something that is virtually impossible to overcome, especially if you learn Spanish, or any foreign language, as an adult.