1st Time Waxing

How long/short does the hair need to be for a sugar wax? Never waxed down there. Just want to make sure it’ll be effective. I always shave and did last night but I want to get a Brazilian or just start with a bikini wax and do that instead…maybe, spending on if I can take it lol 🤣 I want to get one so I’ll stop shaving now so that it can grow a little bit and then I can go get one but don’t want it to be too long. Will they trim it where it needs to be if it’s too long? If it’s too short will they tell me and not do it? Thanks!