Is $60,839 to install 37 REC 450 BOB solar panels with Enphase IQ8X inverters a fair price?

I'm in Massachusetts and looking for help reviewing solar quotes. My roof is getting older and will need to be replaced before I can get solar panels. I estimate my roof will need replacement in about 5-10 years, and I've received one quote for approximately $40,000 for the roof replacement. My biggest question is whether I should wait until the roof absolutely needs replacing before moving forward with solar. I've received two quotes from local installers and am considering getting a few more. The companies that provided these quotes seemed reputable. I suspect that the tax credit issue might be making companies busier until the end of the year.