Alright, managed to track it down by going through the online catalog for the libraries in the county of AZ I checked it out from about 10 years ago. Good thing I remembered where I was when I read it :P I was off on 2 things. One the main character was a male teenager, and two interstellar travel has already disappeared, not is disappearing. The book is Godspeed by Charles Sheffield. Thanks to all that helped.
To the citizens of the planet Erin, the Godspeed Drive is a legendary device from a lost age before the isolation of the Forty Worlds. To teenager Jay Hara, however, it is his one chance to claim his future in deep space--if he can find it. After meeting Paddy Enderton, a seedy old spacer, Jay is drawn into a chase which carries him off the planet, into the asteroid belt and its tiny worldlets, and finally to the remnants of an ancient space station where the Godspeed drive may still exist. The author of Cold as Ice ( LJ 6/15/92) sets this coming-of-age adventure against the backdrop of a planet struggling in quiet desperation to hold onto the remnants of a dying technology.