You can grow out the hair on your mustache area and chin then style it into different types of goatee styles without shaving. If you're not that patient then get a cheap electric beard trimmer or clippers to trim down the areas where you don't want any facial hair; like cheeks , neck and sideburns.
You should never shave your mustache area if you want to have a handlebar. No matter how short or long your goatee is, you will always need the hair on your chin area to have a Handlebar because it can't grow without that.