As a fitness professional, I have to say that it would most likely be a very bad idea to present yourself as a trainer when you do not have a certification backing that up.
Respect the fitness industry and those who work in it by earning the proper credentials to train others, similar to how a doctor doesn’t practice medicine without a medical license.
It’s a matter of principle to me. Training yourself and friends together is one thing, but taking money from someone and providing them with a service is something completely different. I would suggest that if you decide to “get some practice in,” you do it with your friends and you don’t accept any payment from them or set them up with any plans. Legally, that’s the best way to protect your name as a future fitness professional.
People should see you as a professional and not someone who just knows a lot about fitness. Earning that certification is the first step in getting in some legitimate practice. These exams exist for a reason. It’s awesome that you’re going to take your PT exam!