Athletics, 400metre, i am wondering if 56 is a decent time for a 14 year old (in year 8) ? ?

Thats pretty good for an 8th grader, and seeing as how you've had no training. Best way to improve is just keep running, thats all it really takes. If you train hard enough you could probably get down to about a 50 or 49 by the time you are a senior.