Yesterday: You can do it. You don't have to be convinced. You just have to take it day by day or even decision by decision hour by hour, meal by meal, making consistentlyt good decisons in line with your plan, and adding in a bit more random exercise (like parking further away up the street or further away in a car park).
My goal weight isn't 'normal' in that its above the recommended BMI. It was set in discussion with a specialist GP - so it maybe that you will decide to stay at a higher BMI - but one that is much healthier than your current BMI and where you can sustain your new weight. I don't think I'll go lower as I don't want to have a skin flap on my belly and have to have surgery.
So Yesterday - act as if you believe by taking one step at a time.
I'm now less than 2 stone from goal. I haven't been 13 stone something since the early 1980s. Amazing. The reality is that taking it one day at a time will continue to be my mantra at goal as that's when the real work starts - I want to be in teh 30% of slimmers who maintain. It will require as much attention and planning as shedding the weight.
at least 4 stone, maybe 5, i'll see how it goes. i'll either be totally transformed and obsessed by then or i'll think that'll do. it's been so long since i was thin, 12 years and 2 children, that i've no idea what's realistic now.