I've been low in vitamin d for months and i've just noticed a curve in my legs, it might me be being paranoid but is this possible at the age of 17?

Yes, ? rickets: A curve in your leg bones could be a sign of rickets, caused by Vit D deficiency: https://en.wikipedia.org/wiki/Rickets I wonder why you have been low for months. I advise 10,000 iu of D3/day to get your levels up, though you may take 40,000 iu/day for a month to raise more quickly. I would also advise a least 1000 mcg/day of Vit K2 and calcium, magnesium and boron. See http://tinyurl.com/2chkcer