Here's why:
* The dictionary is organized by etymology: It groups words by their origin and how they evolved over time. So, the first words listed are not necessarily the oldest in English, but rather the oldest words from a particular family or source.
* Words are added and updated: As new words appear and older words change meaning, the dictionary is constantly updated, meaning the order of words can shift.
Therefore, there's no fixed "first ten" in the OED.