In a way the complaint is like that of a child who wants to have braces on her teeth. She somehow thinks that braces are neat even though they entail discomfort, care, and maybe ridicule. Ashes are a sign that the person has sinned. It is like the scarlet letter that Hester Prynne has to wear on her dress in The Scarlet Letter.
But, on second thought, a cross of ashes does indicate that we have made a critical choice. They confess guilt, but more importantly express reliance on Jesus Christ for salvation. It proclaims that we do not dismiss our sins as unimportant. Nor do we self-justify them either with an argument of defense or an act of self-absolution. No, the cross of ashes indicates our faith in Christ’s sacrifice as purgative of our guilt. For this reason, it seems right to make the sign of the cross as the ashes fall on her heads.