There are tons of online trainers out there with excellent credentials and experience. They can do your full program for you (training AND diet) or you can choose for them to do just training or just diet. IMO, since you're inexperienced with the competitive thing, if you were to hire a trainer, it would be best to have them do all of your prep setup for you.
Finding someone in your area to actually be with you in the gym from time to time may be a bit tougher. But it really depends on your overall training experience as to whether you'd need someone there with you occasionally or not.
However, keep in mind, it's not a cheap thing to hire a trainer. Some charge monthly, some charge one price for the full package (which usually consists of only the last 3 months). Plus, there are other expenses with the show itself (org membership cards, entry fees, travel and lodging if needed, tanning...).
IMO, wait until the show that's later in the year. 5 months til the first one, and you're sitting at 21%? There's no time for you to try to bulk in that time frame (which would put you at an even higher BF) and then get back down to single digits in time.