Hi my washing machine has started to smell of rotten eggs its only 6 months old and dont no what the problem could be

Possible that the smell is coming from the motor/inlet valve/ pump or the capacitor of the motor. so it is important that you need to have a closer observation to find the source of the smell.
Sometimes it can also be due to drain block and so the dirt accumulation could be stinking. If so remove the drain and clean the hose and fitting , back flush the pump and reset.
check for cleaning on the link below:

http://www.repairclinic.com/Washing-Machine-Troubleshooting?red=Washing-Machine-Repair-Help

Your unit has a build up in it. Here is a trick I uses, set your washer on Hot and the longest wash cycle, use dish washing detergent, not dish counter soap. It has and ingredients in it that will stop the build up and clean out the unit at the same time. If you don't want to waste water, add house cleaning towels to your load.
Good luck, this does work...

I’m happy to help further over the phone at https://www.6ya.com/expert/gere_bf68e6055dd61249