The average 100 yard time for a 7 year old boy depends on which stroke they are swimming and the length of the pool. A typical time for a boy younger then 10 swimming the 100 yard freestyle is 1 minute 10 seconds.
A fast time would be atleast a 25.
For the average 14-year old boy, I would say the average 50m free time would be about a 29.40 sec.
A good time would be 29 seconds.
edward roberts of alton,il. swam a 13.38 on 7/22/2012