You should get a professional bike fit because you are already making the financial and time investments into cycling and riding without an accurate fit on the bike can negate those investments. Having an accurate fit on the bike ensures that you are not only comfortable but are also going to minimize the chances of having an overuse injury.
The last thing you want with something that you do for fun, or career even, is to not be able to ride because you didn’t take care of a minor adjustment that needed to be done on the bike. A professional bike fitter knows the ins and outs of everything related to fits whether it’s an anatomical irregularity or just a sore back or knee while riding. They can get you rolling faster and help prevent any overuse injuries.