Aveilus and new purchases

Question

My wife has been in aveilus for her mother for about 6 mos. She recently bought a new shaitel, but was advised that she should not wear it until she is no longer an avel. I find that very difficult to understand, in that wearing a shaitel is not for convenience, but for halachik reasons. Am I missing something? I told her that she can wear it now. I told her that I would ask you. Kol Hakavod