Crossfit is absolutely the way (along with diet) to get you where you want/need to be. Even the lame Crossfit gyms (there are some) will be beneficial. Nothing Crossfit is doing is rocket science but fitness is handed to you on a silver platter if you put in the work.
You can diet and lose all the weight you want but without strength you are just a skinny weak person.
Also you will realize that a goal weight is stupid since with quality training, you will probably not lose as much as you expect.
I am 44, 5'10, 190# I Crossfit and I would gladly take on anyone in my department in a test of overall fitness.
In Omnia Paratus