If your hair is already quite a light blonde Will bleaching it platinum blonde completely ruin like your mum says?

Another user suggested: Bleach isn't that good for your hair...but if you want it lighter get highlights I suggest: Highlights involve the same color removal that bleaching does...So the same damage.

Damage happens with color removal. The lighter your hair color is, the less damage caused. If you already have light blonde hair, yes, it will cause damage, but it won't cause the same damage that a brown haired girl would suffer from. If you plan on going through with the bleaching, don't wash your hair the day before and the day of the bleaching (you want to maintain as many oils as you can, since bleaching can be stripping) and you want to condition with a special intensive conditioning treatment, post bleach.