Is ablution (wudu') and prayer valid if the person performing ablution wipes their ears and a part of their head, then wipes the rest of their head after forgetting it, without re-wiping the ears?

Many scholars permit women to wipe only part of their head during ablution. Wiping the ears is a Sunnah according to the majority of scholars, and ablution is valid even if it is omitted. Your ablution is, therefore, valid without any doubt. It is advisable to ignore and disregard obsessive thoughts and not to repeat ablution or prayer because of them.