Of course, there's no way anybody could be that inarticulate and amount to anything.
And, your accent is not fixed at one point in life. If you were to move to a different part of the country today, in 10 years, your accent would likely be at least somewhat different due to subconsciously adopting vocabulary and pronunciations of those around you.
That really depends on the age, and on the level of self-consciousness around the accent, notably whether people struggle to understand you. It's very common to not change accents at all after 20.
Here's Christopher Hitchens 30 years after he moved to the US.
