Basically you are a gay virgin, and as such, your first time is probably going to be a bit stressful/anxious. It will feel a bit intimidated, clumsy, awkward and afterwards you may question whether you did the right thing or not. If you chose the right guy, hopefully these feelings will be a lot less.
These things are all normal and a natural part of being inexperienced. Same as when you first learn to drive.
With experience and an openness to learn and experiment, in the end you will probably be more satisfied than you've ever been in your life.