movie about an 8 year old sayibng she was 26

An 8-year-old boy runs away from home and meets a scientist, who transforms him into a young man of 28, although mentally, he remains a child.

A girl becomes curious about a boy in her neighborhood who claims he's 56, but looks to be no older than 16.

A 12-year-old girl goes on a car ride with a man she met online to prove she is not a child anymore.