No you shouldn't be worried.

The ATO only start their full processing of tax returns from the 6th July this year, even though they accept them earlier. That's still a full week earlier than previous years. Last year we had clients who didn't hear anything back for a couple of months! Because they put a "new improved system" in and well, we all felt the result. But the ATO have sent all tax agents out a statement saying they believe they will process 94% within 14 days though to add possible time for people who need to be cross-referenced ie-with child support of the family tax office.

In other words, if you get anything back before the 20th July you would be very lucky. Give it to the end of the month before you chase it.