Newbie needing advice

Hey everybody. I'm on the verge of dying my hair light, light blonde. Possibly platinum. I have short, highlighted hair. Here's a picture:



First of all, do you think I would look good with platinum hair? If not, what color blonde would be best?

Secondly, how long will it take to get my desired platinum color? I will be going to a hairdresser that I have been seeing for the past year and a half.