The DPO is really not any indication as far as when you will be able to pick up pregnancy hormones to show positive on a test. Some people can get a positive HPT at 7DPO and others will not get a positive until weeks later. It all depends on when implantation takes place. Unfortunately there is really no sure way of knowing when the fertilized egg implanted. Generally, most women just start testing a few days before AF would be due. So, you don't to test too early because of the chance of getting a false negative, meaning you are pregnant, but because you dont have enough HCG in your system, you would get a negative HPT. HTH
I started testing right away and I got my first POSTIVE on day 7 after my transfer. I think she is right everyone is different so its hard to tell. I would wait at least 6 days and try!!!! Good Luck!!! I know the waiting period can be hectic