There are many possible reasons for that. You may be the only person in your family with a genetic marker for OCD.
Because of this, you had a higher probability of developing it. Or you were the only person to get PANDAS in your family, and therefore your OCD was a result of a strep infection.
It is possible that you are the only person in your family who had a reaction to an intrusive thought that led to obsessive thinking or the desire to do a ritual. When you did the ritual, it felt relieving, leading to the chance of that happening again in the future.
Whatever the reason, it does not say anything bad about you as a person, it just means that you have a difficulty, and you need to get help for it.