Is it permissible for me to perform Hajj on behalf of my deceased mother, who had not performed the obligatory Hajj, even though I have not yet performed Hajj for myself?

A Muslim who wishes to perform Hajj on behalf of another must first have performed Hajj for himself. The evidence for this is the hadith (definition) of Ibn Abbas, in which the Prophet, peace and blessings be upon him, heard a man say, "Labbayka on behalf of Shubrumah." He asked, "Have you performed Hajj for yourself?" The man replied, "No." The Prophet said, "Perform Hajj for yourself, then perform Hajj on behalf of Shubrumah."