You also mentioned you have thin hair, by which I think you mean "fine" hair (mine is fine also, but it used to be "thick" before it "thinned out", and now I'm pretty well just bald). The opposite of fine hair is, of course, coarse hair. Fine hair is more easily damaged by processing (dying, perming, straightening) than coarser hair, and there are differences between straight and curly as well. So if you do anything to it, make sure it's done by someone experienced with the process on several types of hair - the amount of time for the different processes needs to be adjusted accordingly.
Otherwise, you're going to do more harm than good. The first time I shaved my head was after most of it fell out from a particularly bad dye job for a theatre production in college... and I'm told I was lucky it grew back as well as it did!
Referece; My wife, a professional stylist until carpal tunnel took away her ability to roll perms and hold scissors... we used to talk about hair chemistry all the time, it's fascinating stuff!