Is it okay to dye hair twice in one and will it be even my root have grown out a lot about 3inches and it is dirty blonde?
Why are you writing "dirty" blonde? It is "dark" blonde for ever more. Is there "dirty" red and brown? NO!
Unless you have a friend to help you (that knows what they're doing with hair colour and bleach) this will be very time consuming and tricky to do on your own. It's really not a good idea to dye and highlight your hair in one day, highlights usually require bleach. I would do the colour then the highlights and give your hair a good deep conditioning treatment when you're done. If you've never dyed your hair before or bleached it on your own, then I would strongly suggest seeing a professional and having them do it. If you can find some pictures of what you want to achieve, bring them with you.
Go to a hair salon and have a consult