Me and my mum used to do it all the time. Got cut there too, never had any problems they are all at a certain stage of their training and well supervised. I recommend it to everyone. Have also been done by the junior at my usual hairdresser on a training evening and that was free again supervised and no problems.
i have had it done, what i wanted was some nice soft honey and caramel hightlights what i got whats straw blonde, and at first i thought i could live with it, but i couldn't and in the end i went back in and had some kind of treatment that softened them up, which was free of charge (phew) bad thing about it was they called the trainee in on her day off to come do it so she could learn from her mistake