machan, if you cant flirt then dont do it. if you have been already a good friend to her, that means you have been close enough to her to ask out. flirting isnt the only way to get it going. even though it can, we dont know what sort of impression would she get through that. flirt is the best option if you find a good hot looking girl and if you want her to be your gf for a short time

so, i suggest you to go and ask out. you dont have to be a superman to impress her. expect her to be impressed by the way you normally act in your day to day life. if she does, shes the one for you. each girl is different, so theres no single answer that could work anywhere.