So I got a free month of game time on my wow account 2 days ago for RaF and I started a Mage he Is currently lvl 40 ( maxed out my profs or I'd be higher enchant 300 tailor 300) I have three boas and I was just wondering how long it would take to get to 85

IF your leveling frost, it's very easy. I hit 1-85 in about 60 hours played ( some of those hours are afked). It's really quite easy, so considering your already level 40, I'd say you'd have to play maybe another 30-40 hrs. It also depends on experience though, I've been playing for 5 years and know the inside outs of the game, but you really don't have that long to go, once your 58 and hit Outlands, it's a matter of not getting bored of questing. Good luck!