It's possible it could work for you, but every post I've read about anyone having their hair thinned was negative. It tends to look good immediately, but it's horrible when it's growing in.
I'd suggest instead leaving it the current length, and adding some long layers just to lighten it up a little bit. Especially in that longer haired picture, I can see how it would get heavy and weighing at times.
The pews never miss a sermon but that doesn't get them one step closer to Heaven.
But at least the pews never attend yoga!