I'm about 175cm, I think that's 5' 9"? At 72.1kgs (158lbs?) I've still got a bit of flab around my belly and thighs, but not a huge amount.
BMI puts me in the normal category, but on the higher end. If I can get to 65kg (143lbs) I'd be pretty much dead centre of the normal BMI (and that extra 7kgs would take care of the little bit of flab I've still got). I know BMI has a huge number of flaws, but I'm pretty happy that it suits me. I'm not overly athletic and have a pretty average build, so I'm one of the few that it works for. If you've got a bigger build, or more muscle, you can get away with more weight without looking flabby.
The only way to be sure is to lose it and see. I weigh myself most days and plot it in an iPhone app. I wish I'd taken photos as well, sometimes it's hard to tell how much you've changed because the changes are so gradual.
Good luck! It's hard work, but absolutely worth it. I've got more energy, better moods, and I've cut down my risk of heart attack/stroke/diabetes etc.