Given your height and current weight, I think you could aim for a goal of 60 lbs less + 5 lbs of muscle, so you'd be looking at 120 lbs.
It will obviously take time and no rubbishy pills and shortcuts will get you there, only hard effort, self belief and knowing that you are going to a much better physical place and hopefully that includes a good long life.
Be proud of yourself, for recognising the need for change, for valuing it and for realising you are worth more, than you may have previously considered yourself to be worth.
Although a tough thing, the easiest part is to admit change is necessary, then the harder step is to make it happen, but the toughest part is sustaining what you worked for and not regressing back to a lesser physical state.
If you really want this then you will make it happen. It's something many can do, but less achieve, because it's about their own belief and their abilty to want to change things, if they don't quite start working as well as was expected and not giving up completely.
There are people here, many of whom are female, who have doubted, dispaired, worried, felt upset, ashamed, embarrassed and self inflicted moments or periods, of emotional self destruction, because of perceived lack of progress, but one thing those still posting here have proven, is that they have never given up on themselves and still continue to find or want to find, a way forwards, no matter how often they have slipped up or taken knocks.
So you're not alone here and you're amongst males and females, regardless of the similarity or lack of, to your circumstances, who can and / or will understand, what you will be going through.
You have the self worth of someone more than you currently are and it's about remembering that and letting it grow with time, by using the right eating and exercise methods, to make the end results happen and continue to last.
I'm sure if you really believe in yourself and prove you can make it to the end of the first month, relatively mistake free, you will be well on your way to the new you, I think you deserve to be.
So I wish you well and I hope one day, you will become a great example of womanhood and humankind to others and become someone who can inspire and thought provoke, with your past efforts.
GOOD LUCK and anything you need don't hesitate to let us know and anything you have to offer to anyone else, even one little word, can make such a difference