thanks for letting me know. While I was waiting for a reply, I had called my travel agent back, she was the one who gave me the site I looked at telling me the dimensions.
I did go to seatguru.com and a couple of others. The seats are in fact listed as 17 to 17.5, much better sounding than the 15...
I started reading comments from people that have flown and everybody was more complaining that the seat in front of you encroached on your space the entire trip... and no leg room. Only one person said the seats were way too narrow.
I guess, I will just do my best to get down to where I was that summer I flew and fit okay. haha I know too, that it is going to be hard to determine really, since they are part of the star alliance, which was explained to me by the Travel agent, that it could be a number of carriers partnering with Lufthansa.
all I can do is try and get my weight down, really, plus, I retest my blood in a month with my doctor, due to being recently diagnosed with type 2 diabetes, but my numbers were so close, he will then tell me what my next steps are, so I think diet and exercise will help all the way around.