How can you "want to" convert to a religion? That makes no sense.
You either believe that religion's teachings, or you don't.
Just believing in a religion's teachings doesn't necessarily make you a member of that religion. You have to practise that religion as well. Islam requires you to declare your belief in front of witnesses. Certain forms of Christianity might require you to be baptised etc.
I'm a white girl who wants to convert to Islam, marry a muslim man and wear a burqa. Is this possible at all?
I am very serious.
Your other posts make me reluctant to believe you however, if you are serious then yes, you can. I know of a few converts who have done so, it doesn't matter what colour someone is, you can do what you like, there'll always be people who judge but there'll also always be people who approve. If it's what you really want, go for it.