What vzuden said is only correct if you or someone else added brake fluid. If none was added then you still have the original volume of fluid and the level will just return to it's original level. Because the bike is new to you, you have no way of knowing so what he said is very valid.
While we are on the subject, though, are you aware that all hydraulic fluids (clutch and brake) should be flushed and replaced at regular intervals?? My personal interval is every 4 years but others may say every other year. Brake fluid can and will develop moisture in it reducing it's effectiveness, and cause all sorts of other problems as it really ages. I have seen really old fluid actually crystalize and plug up calipers and master cylinders. You can't tell the condition of your hydraulic fluid from the master cylinder because for all intents and purposes the volume in the reservoir never moves past the master cylinder, it can look clear and clean while the "working" fluid in the lines and caliper could be, and most likely is, a nasty black color.
Yes, the same DOES apply to automotive brakes but very few people are aware of this. Let's face it, the average Cage driver only knows how to put the key in it and put gas into it, everything else is a total mystery...