If you don't read British literature from the 18/19th century generally then I think you might find you have to persevere through the first few chapters.
Personally, if I've gone a while reading only contemporary novels then when I re-read an Austen novel it takes me those few chapters to get used to the language again, but I think that is natural. We don't use that style of writing anymore so of course you should expect to spend a small amount of time getting used to it.
For this reason, as Peachey pointed out, many people will find it extremely rewarding to read a challenging novel, as opposed to a form of literature they know they can pick up and read easily but maybe not really learn anything from. There is a great satisfaction gained from being able to read into the subtleties of 19th century literature, Austen's work in particular is rich in underlying themes and symbols.
I think it's a shame that people shy away from what they perceive to be a 'difficult' style of language if they are a native speaker, because you are not just reading a novel you are gaining an insight into a society and culture which has been sadly lost, and a perspective of the world which you might not have considered before.
I would urge anyone with a comprehensive understanding of English to read a Jane Austen novel, especially if you find it diffiicult, I think you would be surprised at how much you could learn.