A good time for 100 meter dash for your age is 11-12.5 seconds.
is 42 seconds a good 300 meter girls time for a 17 year old
a 11.9 and lower is a good time
that is very good
A really good 100m dash time for a 17 year old would be anything faster than an 11.5
1min 10secs should be a good time