Qada Salaah

i did not wake up for fajr one morning and i only made qadha after reading zuhr. however later on i heard that a person who does not have any qadhas to cover up for their life time should first perform the fajr and then only the zuhr. otherwise the zuhr would not be valid. is this true? i do not have qadhas. the only time i miss my salaahs is when it happens totally unintentionally (does not happen often though) and i cover up immediately. so where do i stand with that qadha i made?

jazakallah