Oh my gosh. . . those guys are so adorable!!

But I think your right, I dont think they're old enough yet.
I was looking around on the avianbiotech website and found these FAQ's. Just thought I'd post them if anyone else was wondering the answers to feather sexing.
Which is more reliable, blood or feather testing?
DNA remains the same regardless of where it is extracted. Both tests are equally accurate.
How many feathers are needed for testing?
We recommend sending at least five (5).
Are freshly plucked feathers necessary for accurate results?
DNA takes an extremely long time to break down, however, testing is likely to be more successful if feathers are freshly plucked.
Can molted feathers be used?
We do not recommend sending molted feathers simply because they tend to carry much less usable DNA, and we want to be certain that the feather is from the bird being tested.
Will feather sexing promote feather picking?
No. Feather picking is generally a neurotic disorder that is not started by plucking a few chest feathers from your bird.
Will the feathers grow back?
Feathers generally grow back in 4 to 6 weeks.
What tests can be performed using feathers?
DNA sexing and PBFD testing are the only assays we offer using feather samples. In the future, we will be able to DNA fingerprint from feathers as well.
Does a bird have to be a certain age?
From birth to death, DNA remains the same across all species, so there is no age range for the most accurate results.