Hi Blondi and welcome!
I don't think any of us are thinmking that about you for trying to lose weight at 17. Most of us realise that child and adolescent weight problems are unfortunately on the increase and most of us would be happy for you that you have so much insight to battle this problem now while you are young!
I also have one of those sisters who just has always been skinny. So much so she had to sit around for a year and eat junk food just so she could buy trousers that fit her waist and weren't half way up her legs length wise!! I know what that's like
Anyway, good luck with your plan,. 1/2kg per week is realistic I think.
35kg lost. (November 2005 - October 2006)
15kg gained again (as at October 2010).
Back to the drawing board - Let's do this thing!
"You can't change the winds, but you can change the sails"
"Reach out and take control of what lands in your lap"