The recommendations nowadays say that you should make up the bottles as you go along, but alot of us dont as it's just not feasable with a screaming hungry baby!
There's a couple of ways to make the bottles up in advance.
Alot of the girls on here make up the bottles the way you do it. As long as the bottles aren't being stored in the door of the fridge (temperature changes as the door opens and closes) then it's all good. It's how I used to do it with my first daughter, but found I prefer to do it the way I do now.
I make up the bottles for the day with just boiled water, and then leave them on the worktop (out of direct sunlight etc and for no more than 24 hours) and just heat up the bottle and add the powder (which we measure out into powder dispensers - Mothercare, Tesco and Amazon sell them quite cheaply) when needed. Works well for us as it doesnt take as long to heat up a room temperature bottle compared to a fridge temperature one - Evie wont take room temp bottles!