My first advice is being patient and put the ego in the pocket. Each of your ego-showing activities will end with the same reaction from the higher belts. The basis is not to fight on the tatami only to learn. You are at the first steps stage, so what do you want to show? relax, learn basics like close guard, side control, kesa gatame, mount control and escapes. These are absolutely fundamental basic to learn from the beginning.
You are 50 years old does not mean anything, sport is for everyone, depends on how you approach it, the more relaxed it’s better, remember that the ligaments and joints are not as strong as before and any unnecessary injury will eliminate us from the BJJ and the gym. Remember to earlier Tapin out why? because it’s better to tap out and continue to sparring like having something broken and training off 3-6 months. Do not try to do things which you do not understand, always ask the instructor, then you will see that “the ego” is just a trap in this sport
I had many bodybuilders on the tatami and after a few minutes of sparring their ego fell to a minimum.
Strength is not everything, some of the bodybuilders accepted tapin with humility and they learned further and others with the broken ego were never coming back. Sometimes I do not even take a sparring just to prove something, it does not make sense. The most important thing is that BJJ must give you pleasure if you take pleasure in it, then you will take the first step, remember everybody was beginner and to get to the next belt you should leave a liters of sweat on the tatami. This is just beginning…….