Can't ever imagine being under 206lbs

I've just been reading the thread about women over 5.10 and their ideal weight - OMG I have been very overweight since my teens - I did get down to 14st 10lbs at uni but that's the lowest I ever remember being. I feel a bit overwhelmed that 140lbs might be the right weight for me - my mum is 9 stone and 5ft 8 and looks too thin to me so for me at nearly 6ft to be even 10 stone I think I might loo way too thin but having said that I've no idea. I look at pictures of me at 14st 10lbs and I think I look lovely and slim and long to get back to that. I guess the nearer I get to my first goal of 206 I can then decide. I thought 140lbs was a big amount to loose another 66lbs seems to scary to contemplate I will never be slim lol!