Dont be an eager beaver mate,when i started at 17 I was mixing browning in a bath and mixing skim with a stick and bodger,for 2 plasterers I would also cut plasterboards for them once they gave me the measurements to save them getting up and down off there milk crates when boarding ceilings the only thing they let me do with the gear was rule off the screeds they floated on the walls and would let me devil float it up I did this for a year at least I even questioned it myself then one day they just started letting me on the tools but when I had free time after mixing passing them gear cleaning the tools etc I was always watching closely asking them questions I was lucky they was 2 sound guy's aswell who was great with me,my advice stick at it be patient they will let you on soon enough or when they think your ready