SMG is a great option.
AG can be the easiest climb on the perfect day, but can also be completely dangerous depending on weather, time of year, rockfall, how many people on route and your experience level.
Don't underestimate it, esp. the elevation.
I'd get some ice axe/crampon experience, take a day course, even it that is in Tahoe and practice on smaller peaks like Lassen or Round Top before doing Shasta. Do a winter snow camp and you'll be better prepared for Shasta. And it will be more enjoyable.
With some experience, you could skip the two day course and use that dough to buy gear.

Take Vitality's post with a grain of salt. Lots of hikers to it this way and I think they get pretty lucky when considering all the things that can go wrong.