Kizoku Yamemasu Shomin ni Narimasu

The protagonist was born to an Earl father and a deceased commoner mother, which led to a restrictive life as an illegitimate child. Now 16 and legally an adult, they choose to leave their aristocratic lineage and register as a commoner. They contemplate whether the knowledge gained from their noble upbringing will be useful in a commoner's life. They also wonder if the practical wisdom and life skills passed down by their mother will aid them in this new path.