Should I buy 2007 Nissan Sentra with 100k miles

100k is pretty high mileage for an 07 - I'd be concerned about buying that particular example, as people who put a lot of mileage on their cars per year often neglect to maintain their vehicles properly - and the ones that drive excess miles while maintaining their cars well often don't sell within the first few years. That being said, a Sentra is a good choice if you're looking for a car that'll be reliable, even after a few hundred thousand miles - although, if you're planning on owning ANY high mileage vehicle(s), I would suggest learning the basics of auto repair/maintenance; it'll save you a few headaches owning a high-mileage vehicle... trust me. :)

Thanks a lot for the response Doran.

Sure thing - I'm happy to help.