That warning light sets off for 2 different things, check 'em both.

Handbrake lever has a flimsy little button switch. You might have to dismantle part of the console (depending on year) to check it. Maybe the bracket is bent or something?

Brake fluid reservoir has a float-switch in the cap. Make sure it's not empty... Sometimes the float gets dirty & sticks. Sometimes it just goes bad.

As your brakes wear down, fluid pumps down to the wheels. If the fluid is low, MAYBE(?) your brakes are about worn out. If you fill it all the way now, when you get new brake pads it'll overflow, so just be aware of that if you do your own brakes.