Upvote:2
Your proposed itinerary is only 13 calendar days in the Schengen area. Your visa allows you to spend 15 days in the Schengen area. This is perfectly OK.
Your departure from the Schengen area is also the day before the last day of visa validity. This is also perfectly OK. You may remain in the Schengen area until the end of the day (23:59:59) on the date of visa expiration.
There is no problem with this itinerary. Even if there is a problem with your flight and your departure is delayed a day, you still have enough time to leave the Schengen area without overstaying.