Yes, that's a complete myth. It's normal for females to start making infertile clutches at about 5-7 months of age, but it's generally preferred not to breed her with a male until she's over a year old. We try to keep the girls from making infertile eggs whenever possible but it happens and it won't cause problems in and of itself.
The important thing is to keep her calcium intake up (I dust my females' insects a little more heavily and more often) and to provide a good place for them to lay eggs if they have to. The link David gave you is a great one, and there is an excellent video on how to make a laying bin in the breeding section of the forums. As long as her nutrition and supplementation is great and she has somewhere appropriate to lay, egg binding issues become a lot more unusual, at least from what we see here on the forum.