Help? Parents need to get used to me growing up, care to spare some advice?

Ok so im a 15 year old boy now. Recently iv been getting into some deep fights with my parents (Both divorced). Two weeks back I was kicked out of my fathers (although I do not live there). My mum has almost caught me about partying, dont get me wrong, im not this prep/jock kid that ends up in the hospital, im firmly against drinking, it is against my religious beliefs. and Im quite responsible about partying. Anyways. Im prepared for an arguement against my mum who seems to keep telling me 'your too young for this and that' when simply I try to get the point across that soon I will be too old to do 'this and that'.
What should I do in the mean time? And what would be my best choice of arguement when she catches me about these things? My mother doesnt seem to understand (yet) that this is what a normal kid my age in my town does.

Please Help