Large Decorative Mirrors Redecorating Room!!!!?

Redecorating room!!!!? - large decorative mirrors

I am 17 years old.
My room is quite small.
violet light.
I would like a more mature looking room.
Currently, many flowers and butterflies are things. (I'm going.)
I love my quilt. (white to violet, blue, golden flower, as in the middle of the Kiddy not. his most mature)
I have a vintage violet "little" things like a small mirror and a tray of ice cream and purple decorative box. and a beautiful jewelry box in dark wood.)
I wonder if you think my room would look good when a wall black / purple shiny and three other white with blue stripes (small and not all, but rather large paint and interior)?
How much should I paint? and how much would it cost?
Similarly, a good site of decorative items for my room look more mature?
Thanks