put it this way, better start off mapping something that already has a ranked version of the mapset, that way you have a point of reference while mapping or after mapping + you don't need to worry about timing, and try watching pishifat videos and ask around for feedback
underrated advice imo try playing the game more, you'll get a gripe of what you enjoy playing and can implement it into your own maps
most importantly don't expect too much out of this mapping thing, a lot of people starting simply expect too much and end up being let down by sky high expectations they set themselves