http://gawker.com/hollywood-actress-has-played-a-17-year-old-for-over-17-885646311

Actress Bianca Lawson (http://www.imdb.com/name/nm0493161/) was on "Saved by the Bell: The New Class" 20 years ago, and was a teen on "Pretty Little Liars" last year.
Read more at http://www.hitfix.com/tv-tattle#RIB2Y1kkgPHF5iB6.99

Not many actresses look young enough to play a teenager when they're in their 30's but she could still pass for one. She also plays a guidance counselor on the MTV show Teen Wolf.

She was also "Kendra, the Vampire Slayer" in season 2 of "Buffy".