Too many unanswered questions to say "yes" or "no" regarding buying this house. Your agent needs to do their homework for you and find out why it's been on so long. Overpricing and location may be the answer, but it could be there are other issue which require work or resolving.
What is owed on the home? What are the taxes? What is the assessed value? Have their been previous offers which were later rescinded? Has it been inspected and are the results available anywhere? Have you reviewed the seller's disclosure statement?
These are just a few questions that come to mind. Others will develop depending on the answers received.
If it's a solid house that was just mismarketed, overpriced for too long and is now within a reasonable value, it may be a good buy. If there are other issues, it may still be too high and an even lower offer may be worth trying. Hard to say without a lot more facts.