Another SS user here. Probably the best program out there (specifically the Novice Linear Progression).
As to the comment above about tendons and such; if your form is correct, tendons will not be an issue (that is, after all, the point of a NLP). The only difference with age, is that an NLP will be much shorter (like 3-4 months...maybe). Form matters, so like mentione dfurther up, get your form checked by a SSC (they have online form checks that are free, and also now have online coaching as well).
As to stretching and such, meh, just perform your warm up sets correctly, and that is all the stretching you will likely need (I mean, warm up sets are stretching and getting blood flowing into the muscles that will be used, why screw around with some nonsensical stretches that may or may not affect the muscles you intend to stress?).
Finally, buy the book; it's money well spent. If you're over 40, get the Barbell Prescription as well (strength training focused on older lifters). BBRx is not a replacement for the SS book, merely an addendum for older lifters.
Be prepared to be tired, eat a crap ton of food, and learn to be sore for weeks at a time. Very few people who start SS's NLP ever finish it, because it's friggin hard. That being said, if you do manage to make it to the end of the NLP, you'll have likely put on a crap load of muscle mass, and shed a fair amount of body fat. Even at 47 (when I started) I still put on about 25lbs of muscle mass in a year. I still follow it, but have advanced to intermediate programming, even with current health related issues (in fact, it has been a HUGE benefit being physically fit in dealing with all the current health related drama).
Their forum also has a fair bit of information...