I believe the service interval for brake fluid is replacement every two years. It would seem like you could be at the second 2 year service interval for brake fluid now. Page 118 of my 2009 vert manual discusses what there are service reminders for. Older brake fluid may contain more moisture which can lead to corrosion issues in the brakes and worse stopping performance, especially if you have to brake hard or repeatedly. My 2006 SUV still has the original brake fluid, however, with no obvious ill effect. I would change it or have it changed but I don't think its a "drop everything" situation.
There is also a warning for brake fluid level discussed on page 138 of my manual. It is supposed to be red and indicates low level of fluid. This should come up without you using the turn stalk to investigate the service interval data. It sounds like you were checking service intervals when you saw this but if it just came up without you checking, it could be the level. You do not want air to get into the system. It doesn't come out easily and will more drastically affect braking. I'd check level before driving again if you think it could be this.