How oldDuring Build 2015 Microsoft promoted its Face detection APIs with a website named The website can either detect your face or use your photo to tell you how old you look. Microsoft has now made an app out of this service and decided to release it to Windows Phone store.

How-Old features:

A fun App to tell how old you look.
1.	Enhanced user interface. 
1)	Guess how old you look
2)	Share the result to weibo, wechat and email

Install link

Thanks Rits for the tip. Cheers!!