Do blind people learn Braille equally fast as the sighted?
I have had a very difficult time finding information that was well-written and what you were looking for. So, I did my best!

From what I have read it takes about four months - everyone is a little bit different and some take longer! Those of us with no visual impairment that try to learn it have no advantage and maybe a slight disadvantage with learning it... I know because I am trying to learn it. It does take a lot a patience and perseverance!

This is the article I referred to: 
Learning braille; how long does it take and does it get harder with age?

Hope this was helpful!