We just returned from our first stay at OKW, and our first vacation with a teenager...DS just turned 13 and we celebrated the entire trip!
We were in a studio #1831, family of 3, and had plenty of room. The beds were super comfy and the pillows were awesome...we all want them for our beds at home. The only thing I wish we had more of was...a bit more surface space. We tend to pile everything in a central location, in this case it was the table which left little space for eating in the morning. The fridge held more than enough for us...half gallon of milk, 2 half gallons of OJ, quart of creamer, a couple pounds of grapes, about a dozen bottles (16.9 and 12 oz.) water, 6 pack of Dr. Pepper, and we had tons of room to spare.
DS swam in the Miller Rd. pool, which was plenty big for him (only 3 ft. - 5 ft. deep so no diving), but he had a great afternoon swimming laps in a slight rain. The main pool, as others said has a new slide...saw an adult on it so should hold a teen. DS wasn't impressed with the game room though.
Overall, DS really like OKW. He really wanted to hang out more at the resort than we did...he was happy they had ESPN on tv so he could keep up with his sports stuff...typical teenage boy.