There are no statutes regulating the title of the monarch's consort AFAIK. We cannot assume then that Camilla will be automatically queen consort when Charles becomes king.
Furthermore, her future title does matter in practice. If she is titled "queen", she will be referred to as "Her Majesty" and princes/princesses of foreign royal houses who are H.R.H's will have to bow/curtsy to her. If she remains "princess consort" only, she will be just an H.R.H. and, most likely, won't get any bow/curtsy from continental crown princes/princesses, with the possible exception of Mette-Marit, who seems to curtsy to everybody (even president Obama and CP Mary of Denmark !).