Picard is born in 2305, and he was promoted to Admiral between 2379 and 2385, and in 2387 Admiral Picard resigned in protest with how Starfleet handled the situation.
The way you behave, New England should still have the British accents and English language of the 1700s. 300 years of societal accent evolution, nevermind 80 years of his career? You really can't say what he has any business his accent being.