Black to a much lighter color

Hello! I have a question and I'm hoping I can get an answer. My hair dye currently is blue and purple. I first dyed it these colors in October but it was just the bottom half of my hair. In December I dyed the top half black and some of the bottom. The last time I re-dyed the black part was 4 months ago in March. I want to bleach all my hair in around August to dye all of my hair blue with some purple. By then it will be 6 months. Am I good to bleach my hair by then? Or will it still be very hard to bleach? Thank you to anyone who responds!