Anytime you bleach your hair it's going to mess it up. It's bleach. If you get it professionally done it'd end up looking a lot better. And you could always buy stuff to keep your hair from being/looking damaged. If there's somewhere near you that sales salon hair products you could ask them what things you need and do it yourself. And if you do have one near you they have shampoo that turns your hair blond if the bleach doesn't do the trick. The one close to me is called Sally's. They sell everything you need to do it yourself. They have everything a salon would. I don't know if you have one. Could be called something else.
First off, I'm a hairdresser, And I have had to do this many times, Use Blond Creme Pre-lightener from Loreal, And if that doesn't make it good enough for you then get a blond hair dye, When the dye wears off the color will still stick because the prelightener is blond. Problem solved.
i'm currently going to school for hair and make up. I would say slowly bleach your hair. That's what I did when I went from black to blond. One week I used power bleach and 40 vol deloper. I used loreal luo color PO2 and it came out white blond or vanilla blond. o and use a deep conditioner for 30 min after bleaching. and a moustrising conditioner and shampoo. I use morccian oil products. And I try to only wash my hair 2 times a week so the natural oils in your hair condition it more.