Your car is pretty new to have a brake fluid loss problem. I would make the fluid level on the reservoir, put a brake pedal depressor tool on the brake pedal and inspect for a leak. If no leak was found I would leave the brake pedal depressed using the tool and come back in half hour (disable brake lights). If no leak was found I would remove the brake master cylinder from the brake booster to inspect the rear seal of the brake master cylinder. Could it be normal brake pad wear causing the fluid level to drop.