Whether you need and/or can benefit from professional assistance depends on aptitude and willingness to study instructions, read carefully, answer accurately and do homework. If you're confident in those areas and have good English language skills, it's very likely, you can be successful doing it on your own, with the help available here.
It is important to note that although it does not matter who is doing the typing, it is the Petitioner (US Citizen) who is responsible for the process. What are that person's aptitude, attitude and willingness? Note also, that if you do hire a professional to help, it is not important where their office happens to be. It's far more convenient for all, if not office appointments are needed.